Xiong Ting
Position: Grad Students
Affiliation: NUS Centre for Advanced 2D Materials
Research Type: Experiment
Email: xiong.t@u.nus.edu
Contact: tel:(65) 9059 0474
CA2DM Publications:
2025 |
Lai, Wenhui; Lee, Jong Hak; Yeo, Zhen Yuan; Yuan, Yue; Liu, Yuqing; Shi, Lu; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos Maria Alava; Rao, Yifan; Xiong, Ting; Lanza, Mario; Loh, Duane N; Ozyilmaz, Barbaros Robust Silicon-Based Anode with High Energy Density upon Dual Welding Encapsulation Journal Article ACS NANO, 19 (43), pp. 38040-38052, 2025, ISSN: 1936-0851. @article{ISI:001598368000001, title = {Robust Silicon-Based Anode with High Energy Density upon Dual Welding Encapsulation}, author = {Wenhui Lai and Jong Hak Lee and Zhen Yuan Yeo and Yue Yuan and Yuqing Liu and Lu Shi and Yanhui Pu and Yong Kang Ong and Carlos Maria Alava Limpo and Yifan Rao and Ting Xiong and Mario Lanza and Duane N Loh and Barbaros Ozyilmaz}, doi = {10.1021/acsnano.5c13278}, times_cited = {0}, issn = {1936-0851}, year = {2025}, date = {2025-10-22}, journal = {ACS NANO}, volume = {19}, number = {43}, pages = {38040-38052}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Silicon has long been considered one of the most promising anode materials for high-performance lithium-ion batteries due to its high theoretical capacity. However, a significant challenge that restricts its practical application is the persistent issue of weak interfacial contact in the silicon anode, which leads to structural instability during lithiation/delithiation processes due to large volume expansion. In this work, we develop a dual welding encapsulation strategy by constructing Si-C chemical bonding between the silicon and conductive covering shells and establishing C-C interlayer bonding connections among the covering shells. By directly examining the interface of silicon-based composites, we identify the types of compounds and hybrid orbital structures from their spatial distribution using machine-learning-enhanced transmission electron microscopy analysis techniques. This dual welding mechanism not only enhances the mechanical strength of the protective carbon shell but also ensures sustained electrical connection between the core and shell through the Si-C bonds. The robust heterogeneous structure effectively mitigates interfacial instability within the silicon anode, suppressing volume expansion below 12% after 300 cycles. Thus, the full-cell with the composite anode and LiNi0.8Co0.1Mn0.1O2 cathode performs a high energy density of 576 Wh kg-1 and stable cycling, inspiring the construction of commercial silicon batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Silicon has long been considered one of the most promising anode materials for high-performance lithium-ion batteries due to its high theoretical capacity. However, a significant challenge that restricts its practical application is the persistent issue of weak interfacial contact in the silicon anode, which leads to structural instability during lithiation/delithiation processes due to large volume expansion. In this work, we develop a dual welding encapsulation strategy by constructing Si-C chemical bonding between the silicon and conductive covering shells and establishing C-C interlayer bonding connections among the covering shells. By directly examining the interface of silicon-based composites, we identify the types of compounds and hybrid orbital structures from their spatial distribution using machine-learning-enhanced transmission electron microscopy analysis techniques. This dual welding mechanism not only enhances the mechanical strength of the protective carbon shell but also ensures sustained electrical connection between the core and shell through the Si-C bonds. The robust heterogeneous structure effectively mitigates interfacial instability within the silicon anode, suppressing volume expansion below 12% after 300 cycles. Thus, the full-cell with the composite anode and LiNi0.8Co0.1Mn0.1O2 cathode performs a high energy density of 576 Wh kg-1 and stable cycling, inspiring the construction of commercial silicon batteries. |
Rao, Yifan; Lee, Jong Hak; Pu, Yanhui; Ong, Yong Kang; Shi, Lu; Lai, Wenhui; Limpo, Carlos; Yuan, Yue; Xiong, Ting; Lanza, Mario; Ozyilmaz, Barbaros Reinforcement-free monolithic all-in-one structural supercapacitors Journal Article CHEMICAL ENGINEERING JOURNAL, 519 , 2025, ISSN: 1385-8947. @article{ISI:001532082000001, title = {Reinforcement-free monolithic all-in-one structural supercapacitors}, author = {Yifan Rao and Jong Hak Lee and Yanhui Pu and Yong Kang Ong and Lu Shi and Wenhui Lai and Carlos Limpo and Yue Yuan and Ting Xiong and Mario Lanza and Barbaros Ozyilmaz}, doi = {10.1016/j.cej.2025.165492}, times_cited = {0}, issn = {1385-8947}, year = {2025}, date = {2025-09-01}, journal = {CHEMICAL ENGINEERING JOURNAL}, volume = {519}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {Structural supercapacitors, potential game-changers for various applications such as aerospace, automotive, and construction industries, offer a combination of energy storage and load-bearing functionalities. Conventional approaches, however, have been hindered by a significant decrease in overall energy storage performance due to the inherent separation of energy storage components and structural reinforcement elements. In this study, we report reinforcement-free all-in-one structural supercapacitors that tailor the conventional trade-off problem between energy capacity and mechanical strength by ensuring that the essential energy storage components possess high mechanical properties. This dual-functional structure ensures that it volumetrically constitutes nearly 90% of the cells excluding the packaging. Simultaneously, by employing interlocking interfacial engineering, we optimize the functionalities of these components, enhancing the overall robustness and energy capacity of the device. Consequently, our structural supercapacitor demonstrates good structural integrity, as evidenced by its flexural modulus of 8.34 GPa. Moreover, our supercapacitor stands out in terms of energy storage capacity, boasting a volumetric energy density of 45 Wh/L. This achievement, outperforming the current state-of-the-art by a staggering tenfold, significantly enhances multifunctionality, a critical index for evaluating structural energy devices, reaching a 9.95 rating. This novel strategy provides insight for other structural energy storage devices with higher multifunctional efficiency.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Structural supercapacitors, potential game-changers for various applications such as aerospace, automotive, and construction industries, offer a combination of energy storage and load-bearing functionalities. Conventional approaches, however, have been hindered by a significant decrease in overall energy storage performance due to the inherent separation of energy storage components and structural reinforcement elements. In this study, we report reinforcement-free all-in-one structural supercapacitors that tailor the conventional trade-off problem between energy capacity and mechanical strength by ensuring that the essential energy storage components possess high mechanical properties. This dual-functional structure ensures that it volumetrically constitutes nearly 90% of the cells excluding the packaging. Simultaneously, by employing interlocking interfacial engineering, we optimize the functionalities of these components, enhancing the overall robustness and energy capacity of the device. Consequently, our structural supercapacitor demonstrates good structural integrity, as evidenced by its flexural modulus of 8.34 GPa. Moreover, our supercapacitor stands out in terms of energy storage capacity, boasting a volumetric energy density of 45 Wh/L. This achievement, outperforming the current state-of-the-art by a staggering tenfold, significantly enhances multifunctionality, a critical index for evaluating structural energy devices, reaching a 9.95 rating. This novel strategy provides insight for other structural energy storage devices with higher multifunctional efficiency. |
2024 |
Lai, Wenhui; Lee, Jong Hak; Shi, Lu; Liu, Yuqing; Pu, Yanhui; Ong, Yong Kang; Limpo, Carlos; Xiong, Ting; Rao, Yifan; Sow, Chorng Haur; Ozyilmaz, Barbaros High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries Journal Article 18 JOURNAL OF ENERGY CHEMISTRY, 93 , pp. 253-263, 2024, ISSN: 2095-4956. @article{ISI:001203104900001, title = {High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries}, author = {Wenhui Lai and Jong Hak Lee and Lu Shi and Yuqing Liu and Yanhui Pu and Yong Kang Ong and Carlos Limpo and Ting Xiong and Yifan Rao and Chorng Haur Sow and Barbaros Ozyilmaz}, doi = {10.1016/j.jechem.2024.02.021}, times_cited = {18}, issn = {2095-4956}, year = {2024}, date = {2024-03-06}, journal = {JOURNAL OF ENERGY CHEMISTRY}, volume = {93}, pages = {253-263}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Despite advancements in silicon -based anodes for high -capacity lithium -ion batteries, their widespread commercial adoption is still hindered by significant volume expansion during cycling, especially at high active mass loadings crucial for practical use. The root of these challenges lies in the mechanical instability of the material, which subsequently leads to the structural failure of the electrode. Here, we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles. This composite features a unique interlayer-bonded graphite structure, achieved through the application of a modified spark plasma sintering method. Notably, this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength (Vickers hardness: up to 658 MPa, Young's modulus: 11.6 GPa). This strength effectively accommodates silicon expansion, resulting in an impressive areal capacity of 2.9 mA h cm -2 (736 mA h g-1) and a steady cycle life (93% after 100 cycles). Such outstanding performance is paired with features appropriate for large-scale industrial production of silicon batteries, such as active mass loading of at least 3.9 mg cm -2, a high -tap density electrode material of 1.68 g cm -3 (secondary clusters: 1.12 g cm -3), and a production yield of up to 1 kg per day. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved. |
Xiong, Ting; Zhang, Deqiang; Yeo, Jing Ying; Zhan, Yufeng; Ong, Yong Kang; Limpo, Carlos Maria Alava; Shi, Lu; Rao, Yifan; Pu, Yanhui; Lai, Wenhui; Lee, Jonghak; Lee, Wee Siang Vincent; Ozyilmaz, Barbaros Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density Journal Article 12 JOURNAL OF MATERIALS CHEMISTRY A, 12 (9), pp. 5499-5507, 2024, ISSN: 2050-7488. @article{ISI:001156660000001, title = {Interfacial design towards stable zinc metal-free zinc-ion batteries with high energy density}, author = {Ting Xiong and Deqiang Zhang and Jing Ying Yeo and Yufeng Zhan and Yong Kang Ong and Carlos Maria Alava Limpo and Lu Shi and Yifan Rao and Yanhui Pu and Wenhui Lai and Jonghak Lee and Wee Siang Vincent Lee and Barbaros Ozyilmaz}, doi = {10.1039/d3ta07674a}, times_cited = {12}, issn = {2050-7488}, year = {2024}, date = {2024-02-02}, journal = {JOURNAL OF MATERIALS CHEMISTRY A}, volume = {12}, number = {9}, pages = {5499-5507}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zinc metal-free zinc-ion batteries hold promise for achieving higher energy densities by eliminating the need for dense zinc foil as the anode. However, the direct use of substrates like copper foil in these batteries results in poor cyclic stability due to dendrite growth. Herein, we propose a strategy to modulate the nucleation sites and growth dynamics of Zn. This is achieved by introducing a graphene coating on the copper substrate, which directs the initial nucleation of Zn to form hexagonal plates. Subsequently, the incorporation of positively polarized poly(vinylidene fluoride-trifluoroethylene) promotes growth along these hexagonal plates, resulting in uniform crystalline plates. As a result, the half-cell demonstrated a significant improvement in the cyclic life of 3000 cycles at a high current density of 10 mA cm-2 and capacity of 1 mA h cm-2. When paired with Zn-inserted MnO2 cathode, the full cell exhibited high cyclic stability (retaining 83% capacity after 500 cycles at 1 mA cm-2) and energy density of 378 W h kg-1 at 0.5 mA cm-2. This is notably higher than the conventional Zn ion battery based on a Zn anode (136 W h kg-1). To showcase its potential, we prepared a pouch cell that successfully powered the electric fan and LED lights, suggesting its promising application in high-performance Zn ion batteries. |
2020 |
Xiong, Ting; Zhang, Yaoxin; Lee, Wee Siang Vincent; Xue, Junmin Defect Engineering in Manganese-Based Oxides for Aqueous Rechargeable Zinc-Ion Batteries: A Review Journal Article 346 ADVANCED ENERGY MATERIALS, 10 (34), 2020, ISSN: 1614-6832. @article{ISI:000553341000001, title = {Defect Engineering in Manganese-Based Oxides for Aqueous Rechargeable Zinc-Ion Batteries: A Review}, author = {Ting Xiong and Yaoxin Zhang and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1002/aenm.202001769}, times_cited = {346}, issn = {1614-6832}, year = {2020}, date = {2020-07-29}, journal = {ADVANCED ENERGY MATERIALS}, volume = {10}, number = {34}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {The development of advanced cathode materials for aqueous the zinc ion battery (ZIB) represents a crucial step toward building future large-scale green energy conversion and storage systems. Recently, significant progress has been achieved in the development of manganese-based oxides for ZIB via defect engineering, whereby the intrinsic capacity and energy density have been enhanced. In this review, an overview of the recent progress in the defect engineering of manganese-based oxides for aqueous ZIBs is summarized in the following order: 1) the structures and properties of the commonly used manganese-based oxides, 2) the classification of the various types of defect engineering commonly reported, 3) the various strategies used to create defects in materials, and 4) the effects of the various types of defect engineering on the electrochemical performance of manganese-based oxides. Finally, a perspective on the defect engineering of manganese-based oxides is proposed to further enhance their electrochemical performance as a ZIB cathode.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The development of advanced cathode materials for aqueous the zinc ion battery (ZIB) represents a crucial step toward building future large-scale green energy conversion and storage systems. Recently, significant progress has been achieved in the development of manganese-based oxides for ZIB via defect engineering, whereby the intrinsic capacity and energy density have been enhanced. In this review, an overview of the recent progress in the defect engineering of manganese-based oxides for aqueous ZIBs is summarized in the following order: 1) the structures and properties of the commonly used manganese-based oxides, 2) the classification of the various types of defect engineering commonly reported, 3) the various strategies used to create defects in materials, and 4) the effects of the various types of defect engineering on the electrochemical performance of manganese-based oxides. Finally, a perspective on the defect engineering of manganese-based oxides is proposed to further enhance their electrochemical performance as a ZIB cathode. |
Xiong, Ting; Zhang, Yaoxin; Wang, Yinming; Lee, Wee Siang Vincent; Xue, Junmin Hexagonal MoO_3 as a zinc intercalation anode towards zinc metal-free zinc-ion batteries Journal Article 111 JOURNAL OF MATERIALS CHEMISTRY A, 8 (18), pp. 9006-9012, 2020, ISSN: 2050-7488. @article{ISI:000536095500018, title = {Hexagonal MoO_3 as a zinc intercalation anode towards zinc metal-free zinc-ion batteries}, author = {Ting Xiong and Yaoxin Zhang and Yinming Wang and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1039/d0ta02236e}, times_cited = {111}, issn = {2050-7488}, year = {2020}, date = {2020-05-14}, journal = {JOURNAL OF MATERIALS CHEMISTRY A}, volume = {8}, number = {18}, pages = {9006-9012}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Aqueous rechargeable zinc-ion batteries (ZIBs) are attractive candidates for application in energy storage technology. However, the formation of Zn dendrites at a potential close to the Zn/Zn2+ redox potential can severely limit battery rechargeability and energy density. Herein, hexagonal MoO3 (h-MoO3) is proposed as an intercalation anode (discharge potential of 0.36 V (vs. Zn2+/Zn)) as a potential replacement for Zn metal plates for the first time and it showed a specific capacity of 120 mA h g(-1) at 0.2 A g(-1) with superior cycling stability. Furthermore, a zinc metal-free full cell was successfully demonstrated with this h-MoO3 anode and a Zn0.2MnO2 cathode. The cell delivered a specific capacity of 56.7 mA h g(-1) which corresponds to an energy density of 61 W h kg(-1) (based on the total mass of anode and cathode materials), higher than that of most aqueous zinc ion batteries. Furthermore, excellent cycling life was recorded as the full ZIB cell achieved ca. 100% of its original capacity after 1000 cycles. Based on the preliminary investigation of utilizing h-MoO3 as the ZIB anode, the results have shown significant promise in achieving Zn ion full batteries for energy storage applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Aqueous rechargeable zinc-ion batteries (ZIBs) are attractive candidates for application in energy storage technology. However, the formation of Zn dendrites at a potential close to the Zn/Zn2+ redox potential can severely limit battery rechargeability and energy density. Herein, hexagonal MoO3 (h-MoO3) is proposed as an intercalation anode (discharge potential of 0.36 V (vs. Zn2+/Zn)) as a potential replacement for Zn metal plates for the first time and it showed a specific capacity of 120 mA h g(-1) at 0.2 A g(-1) with superior cycling stability. Furthermore, a zinc metal-free full cell was successfully demonstrated with this h-MoO3 anode and a Zn0.2MnO2 cathode. The cell delivered a specific capacity of 56.7 mA h g(-1) which corresponds to an energy density of 61 W h kg(-1) (based on the total mass of anode and cathode materials), higher than that of most aqueous zinc ion batteries. Furthermore, excellent cycling life was recorded as the full ZIB cell achieved ca. 100% of its original capacity after 1000 cycles. Based on the preliminary investigation of utilizing h-MoO3 as the ZIB anode, the results have shown significant promise in achieving Zn ion full batteries for energy storage applications. |
Xiong, Ting; Lee, Wee Siang Vincent; Du, Yonghua; Yu, Juezhi; Xi, Shibo; Wu, Haijun; Pennycook, Stephen John; Yang, Ping; Xue, Junmin Bismuth ion battery - A new member in trivalent battery technology Journal Article ENERGY STORAGE MATERIALS, 25 , pp. 100-104, 2020, ISSN: 2405-8297. @article{ISI:000508681700010, title = {Bismuth ion battery - A new member in trivalent battery technology}, author = {Ting Xiong and Wee Siang Vincent Lee and Yonghua Du and Juezhi Yu and Shibo Xi and Haijun Wu and Stephen John Pennycook and Ping Yang and Junmin Xue}, doi = {10.1016/j.ensm.2019.10.026}, times_cited = {4}, issn = {2405-8297}, year = {2020}, date = {2020-03-01}, journal = {ENERGY STORAGE MATERIALS}, volume = {25}, pages = {100-104}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {To provide alternative battery technologies to lithium ion battery, multivalent metal ion batteries with their high theoretical capacities and ease of preparation have gradually gained attention from both academia and industries. In this work, we report bismuth ion battery (BIB) as a promising trivalent metal ion battery, next to the only known aluminum ion battery. Our BIB successfully demonstrates battery behavior with discharge plateaus at 0.5 and 0.2 V. Gravimetric capacity of 300 mAh g(-1) at current density of 0.2 A g(-1) was obtained with ca. 98% coulombic efficiency. In addition, stable cyclic life was achieved after 100 cycles at 0.3 A g(-1) which further suggests its suitability as potential trivalent metal ion battery.}, keywords = {}, pubstate = {published}, tppubtype = {article} } To provide alternative battery technologies to lithium ion battery, multivalent metal ion batteries with their high theoretical capacities and ease of preparation have gradually gained attention from both academia and industries. In this work, we report bismuth ion battery (BIB) as a promising trivalent metal ion battery, next to the only known aluminum ion battery. Our BIB successfully demonstrates battery behavior with discharge plateaus at 0.5 and 0.2 V. Gravimetric capacity of 300 mAh g(-1) at current density of 0.2 A g(-1) was obtained with ca. 98% coulombic efficiency. In addition, stable cyclic life was achieved after 100 cycles at 0.3 A g(-1) which further suggests its suitability as potential trivalent metal ion battery. |
Xiong, Ting; Zhu, Mingke; Zhang, Yaoxin; Lee, Wee Siang Vincent; Yu, Zhi Gen; Xue, Junmin Interlayer Engineering of MnO_2 with High Charge Density Bi^3+ for High Rate and Stable Aqueous Supercapacitor Journal Article 29 BATTERIES & SUPERCAPS, 3 (6), pp. 519-526, 2020. @article{ISI:000526099200001, title = {Interlayer Engineering of MnO_2 with High Charge Density Bi^3+ for High Rate and Stable Aqueous Supercapacitor}, author = {Ting Xiong and Mingke Zhu and Yaoxin Zhang and Wee Siang Vincent Lee and Zhi Gen Yu and Junmin Xue}, doi = {10.1002/batt.202000007}, times_cited = {29}, year = {2020}, date = {2020-02-19}, journal = {BATTERIES & SUPERCAPS}, volume = {3}, number = {6}, pages = {519-526}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Two-dimensional delta-MnO2 has attracted considerable attention as supercapacitor electrode due to its ability to incorporate foreign ions into its interlayer spacing which suggests the possibility of capacitance enhancement through interlayer engineering. Incorporating high charge density cation such as Bi3+ into the MnO2 interlayer becomes an attractive strategy that not only serves to stabilize the layer structure, it is also an important prelude towards the weakening of the chemical bonding between the O from MnO2 and the intercalating electrolyte species. This in turn leads to higher reversibility while ensuring excellent structural stability that is portrayed in enhanced cyclic stability and rate performance. Herein, the Bi3+-modified delta-MnO2 delivered a reversible specific capacity of 421 F g(-1) at 1 A g(-1), which is higher than that of the previously reported mono/divalent cation-intercalant modified MnO2 systems. Using the N-doped carbon nanosheets as the negative electrode, the assembled asymmetric supercapacitor achieved a high capacitance of 77 F g(-1) at 1 Ag-1. Furthermore, the high energy density of 20 Wh kg(-1) was recorded at a high-power density of 39 kW kg(-1), while simultaneously demonstrating excellent cycle performance of 82 % capacitance retention after 40 000 cycles. This work has shown that interlayer engineering of layered MnO2 could potentially provide new insight into the development of high-performance supercapacitor electrode.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional delta-MnO2 has attracted considerable attention as supercapacitor electrode due to its ability to incorporate foreign ions into its interlayer spacing which suggests the possibility of capacitance enhancement through interlayer engineering. Incorporating high charge density cation such as Bi3+ into the MnO2 interlayer becomes an attractive strategy that not only serves to stabilize the layer structure, it is also an important prelude towards the weakening of the chemical bonding between the O from MnO2 and the intercalating electrolyte species. This in turn leads to higher reversibility while ensuring excellent structural stability that is portrayed in enhanced cyclic stability and rate performance. Herein, the Bi3+-modified delta-MnO2 delivered a reversible specific capacity of 421 F g(-1) at 1 A g(-1), which is higher than that of the previously reported mono/divalent cation-intercalant modified MnO2 systems. Using the N-doped carbon nanosheets as the negative electrode, the assembled asymmetric supercapacitor achieved a high capacitance of 77 F g(-1) at 1 Ag-1. Furthermore, the high energy density of 20 Wh kg(-1) was recorded at a high-power density of 39 kW kg(-1), while simultaneously demonstrating excellent cycle performance of 82 % capacitance retention after 40 000 cycles. This work has shown that interlayer engineering of layered MnO2 could potentially provide new insight into the development of high-performance supercapacitor electrode. |
Yang, Lin; Nandakumar, Dilip Krishna; Miao, Linqing; Suresh, Lakshmi; Zhang, Danwei; Xiong, Ting; Vaghasiya, Jayraj V; Kwon, Ki Chang; Tan, Swee Ching Energy Harvesting from Atmospheric Humidity by a Hydrogel-Integrated Ferroelectric-Semiconductor System Journal Article 111 JOULE, 4 (1), pp. 176-188, 2020, ISSN: 2542-4351. @article{ISI:000507640500017, title = {Energy Harvesting from Atmospheric Humidity by a Hydrogel-Integrated Ferroelectric-Semiconductor System}, author = {Lin Yang and Dilip Krishna Nandakumar and Linqing Miao and Lakshmi Suresh and Danwei Zhang and Ting Xiong and Jayraj V Vaghasiya and Ki Chang Kwon and Swee Ching Tan}, doi = {10.1016/j.joule.2019.10.008}, times_cited = {111}, issn = {2542-4351}, year = {2020}, date = {2020-01-15}, journal = {JOULE}, volume = {4}, number = {1}, pages = {176-188}, publisher = {CELL PRESS}, address = {50 HAMPSHIRE ST, FLOOR 5, CAMBRIDGE, MA 02139 USA}, abstract = {Direct utilization of abundantly available solar energy is a promising way to create a sustainable society. Here, we report a ferroelectric-semiconductor (BaTiO3@BiVO4) hybrid that uses an effective strategy to enhance charge separation and transfer during water oxidation. The tetragonal BaTiO3 can induce an outward vector of built-in electric field after positive polarization, which aids in increasing the photovoltage and accelerating holes' transfer to BiVO4's surface. A super-hygroscopic metal hydrogel serves as an atmospheric humidity harvester for continuous water supply to the hybrid, where water oxidation takes place. As the hydrogel absorbs moisture from ambient humid air, it functions as a dehumidifying agent and carries water to the photoanode for power generation, being connected in series with a solar cell, further boosting the carrier's mobility. This photoanode-hydrogel and solar-cell intelligent assembly can generate a photocurrent of 0.4 mA/cm(2) with a relative humidity reduction of 12.0% under an illumination of 10 mW/cm(2).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Direct utilization of abundantly available solar energy is a promising way to create a sustainable society. Here, we report a ferroelectric-semiconductor (BaTiO3@BiVO4) hybrid that uses an effective strategy to enhance charge separation and transfer during water oxidation. The tetragonal BaTiO3 can induce an outward vector of built-in electric field after positive polarization, which aids in increasing the photovoltage and accelerating holes' transfer to BiVO4's surface. A super-hygroscopic metal hydrogel serves as an atmospheric humidity harvester for continuous water supply to the hybrid, where water oxidation takes place. As the hydrogel absorbs moisture from ambient humid air, it functions as a dehumidifying agent and carries water to the photoanode for power generation, being connected in series with a solar cell, further boosting the carrier's mobility. This photoanode-hydrogel and solar-cell intelligent assembly can generate a photocurrent of 0.4 mA/cm(2) with a relative humidity reduction of 12.0% under an illumination of 10 mW/cm(2). |
Xiong, Ting; Wang, Yinming; Yin, Bosi; Shi, Wen; Lee, Wee Siang Vincent; Xue, Junmin Bi_2S_3 for Aqueous Zn Ion Battery with Enhanced Cycle Stability Journal Article 67 NANO-MICRO LETTERS, 12 (1), 2020, ISSN: 2311-6706. @article{ISI:000510847500008, title = {Bi_2S_3 for Aqueous Zn Ion Battery with Enhanced Cycle Stability}, author = {Ting Xiong and Yinming Wang and Bosi Yin and Wen Shi and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1007/s40820-019-0352-3}, times_cited = {67}, issn = {2311-6706}, year = {2020}, date = {2020-01-01}, journal = {NANO-MICRO LETTERS}, volume = {12}, number = {1}, publisher = {SHANGHAI JIAO TONG UNIV PRESS}, address = {SHANGHAI JIAO TONG UNIV, 800 DONGCHUAN RD, SHANGHAI, 200240, PEOPLES R CHINA}, abstract = {Aqueous Zn ion batteries (ZIBs) are promising in energy storage due to the low cost, high safety, and material abundance. The development of metal oxides as the cathode for ZIBs is limited by the strong electrostatic forces between O2- and Zn2+ which leads to poor cyclic stability. Herein, Bi2S3 is proposed as a promising cathode material for rechargeable aqueous ZIBs. Improved cyclic stability and fast diffusion of Zn2+ is observed. Also, the layered structure of Bi2S3 with the weak van der Waals interaction between layers offers paths for diffusion and occupancy of Zn2+. As a result, the Zn/Bi2S3 battery delivers high capacity of 161 mAh g(-1) at 0.2 A g(-1) and good cycling stability up to 100 cycles with ca. 100% retention. The battery also demonstrates good cyclic performance of ca. 80.3% over 2000 cycles at 1 A g(-1). The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. This work indicates that Bi2S3 shows great potential as the cathode of ZIBs with good performance and stability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Aqueous Zn ion batteries (ZIBs) are promising in energy storage due to the low cost, high safety, and material abundance. The development of metal oxides as the cathode for ZIBs is limited by the strong electrostatic forces between O2- and Zn2+ which leads to poor cyclic stability. Herein, Bi2S3 is proposed as a promising cathode material for rechargeable aqueous ZIBs. Improved cyclic stability and fast diffusion of Zn2+ is observed. Also, the layered structure of Bi2S3 with the weak van der Waals interaction between layers offers paths for diffusion and occupancy of Zn2+. As a result, the Zn/Bi2S3 battery delivers high capacity of 161 mAh g(-1) at 0.2 A g(-1) and good cycling stability up to 100 cycles with ca. 100% retention. The battery also demonstrates good cyclic performance of ca. 80.3% over 2000 cycles at 1 A g(-1). The storage mechanism in the Bi2S3 cathode is related to the reversible Zn ion intercalation/extraction reactions and the capacitive contribution. This work indicates that Bi2S3 shows great potential as the cathode of ZIBs with good performance and stability. |
2019 |
Xiong, Ting; Yu, Zhi Gen; Wu, Haijun; Du, Yonghua; Xie, Qidong; Chen, Jingsheng; Zhang, Yong-Wei; Pennycook, Stephen John; Lee, Wee Siang Vincent; Xue, Junmin Defect Engineering of Oxygen-Deficient Manganese Oxide to Achieve High-Performing Aqueous Zinc Ion Battery Journal Article 596 ADVANCED ENERGY MATERIALS, 9 (14), 2019, ISSN: 1614-6832. @article{ISI:000467132300009, title = {Defect Engineering of Oxygen-Deficient Manganese Oxide to Achieve High-Performing Aqueous Zinc Ion Battery}, author = {Ting Xiong and Zhi Gen Yu and Haijun Wu and Yonghua Du and Qidong Xie and Jingsheng Chen and Yong-Wei Zhang and Stephen John Pennycook and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1002/aenm.201803815}, times_cited = {596}, issn = {1614-6832}, year = {2019}, date = {2019-04-11}, journal = {ADVANCED ENERGY MATERIALS}, volume = {9}, number = {14}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {A major limitation of MnO2 in aqueous Zn/MnO2 ion battery applications is the poor utilization of its electrochemical active surface area. Herein, it is shown that by generating oxygen vacancies (V-O) in the MnO2 lattice, Gibbs free energy of Zn2+ adsorption in the vicinity of V-O can be reduced to thermoneutral value (approximate to 0.05 eV). This suggests that Zn2+ adsorption/desorption process on oxygen-deficient MnO2 is more reversible as compared to pristine MnO2. In addition, because of the fact that fewer electrons are needed for ZnO bonding in oxygen-deficient MnO2, more valence electrons can be contributed into the delocalized electron cloud of the material, which aids in enhancing the attainable capacity. As a result, the stable Zn/oxygen-deficient MnO2 battery is able to deliver one of the highest capacities of 345 mAh g(-1) reported for a birnessite MnO2 system. This excellent electrochemical performance suggests that generating oxygen vacancies in MnO2 may aid in the future development of advanced cathodes for aqueous Zn ion batteries.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A major limitation of MnO2 in aqueous Zn/MnO2 ion battery applications is the poor utilization of its electrochemical active surface area. Herein, it is shown that by generating oxygen vacancies (V-O) in the MnO2 lattice, Gibbs free energy of Zn2+ adsorption in the vicinity of V-O can be reduced to thermoneutral value (approximate to 0.05 eV). This suggests that Zn2+ adsorption/desorption process on oxygen-deficient MnO2 is more reversible as compared to pristine MnO2. In addition, because of the fact that fewer electrons are needed for ZnO bonding in oxygen-deficient MnO2, more valence electrons can be contributed into the delocalized electron cloud of the material, which aids in enhancing the attainable capacity. As a result, the stable Zn/oxygen-deficient MnO2 battery is able to deliver one of the highest capacities of 345 mAh g(-1) reported for a birnessite MnO2 system. This excellent electrochemical performance suggests that generating oxygen vacancies in MnO2 may aid in the future development of advanced cathodes for aqueous Zn ion batteries. |
2018 |
Xiong, Ting; Lee, Wee Siang Vincent; Xue, Junmin K^+-Intercalated MnO_2 Electrode for High Performance Aqueous Supercapacitor Journal Article 56 ACS APPLIED ENERGY MATERIALS, 1 (10), pp. 5619-5626, 2018, ISSN: 2574-0962. @article{ISI:000458706600056, title = {K^+-Intercalated MnO_2 Electrode for High Performance Aqueous Supercapacitor}, author = {Ting Xiong and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1021/acsaem.8b01160}, times_cited = {56}, issn = {2574-0962}, year = {2018}, date = {2018-10-01}, journal = {ACS APPLIED ENERGY MATERIALS}, volume = {1}, number = {10}, pages = {5619-5626}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {MnO2 is often considered to be a promising supercapacitor electrode due to its unique electrochemical properties. This is largely due to the various arrangements of the corner and edge sharing MnO6 octahedra that form a variety of sublattices. Not only do the interstitial sites that are generated in this process allow the occupancy of alkali, alkali earth cations, and water to stabilize the MnO2 framework but also the process itself requires energy which is competitive against probable oxygen evolution reaction. Owning to its higher mobility and higher conductivity as compared to common alkali cations such as Li+ and Na+, K+ was selected as the intercalating cation to form K0.6MnO2 and it was used as positive electrode. When paired with K+-adsorbed holey carbon as the negative electrode, the 2.4 V asymmetric aqueous supercapacitor was able to deliver 52.8 Wh kg(-1) and power density of 58.4 kW kg(-1). A good cyclic life of ca. 95% capacitance retention was also demonstrated after cycling for 10000 cycles at 20 A g(-1)}, keywords = {}, pubstate = {published}, tppubtype = {article} } MnO2 is often considered to be a promising supercapacitor electrode due to its unique electrochemical properties. This is largely due to the various arrangements of the corner and edge sharing MnO6 octahedra that form a variety of sublattices. Not only do the interstitial sites that are generated in this process allow the occupancy of alkali, alkali earth cations, and water to stabilize the MnO2 framework but also the process itself requires energy which is competitive against probable oxygen evolution reaction. Owning to its higher mobility and higher conductivity as compared to common alkali cations such as Li+ and Na+, K+ was selected as the intercalating cation to form K0.6MnO2 and it was used as positive electrode. When paired with K+-adsorbed holey carbon as the negative electrode, the 2.4 V asymmetric aqueous supercapacitor was able to deliver 52.8 Wh kg(-1) and power density of 58.4 kW kg(-1). A good cyclic life of ca. 95% capacitance retention was also demonstrated after cycling for 10000 cycles at 20 A g(-1) |
Xiong, Ting; Yu, Zhi Gen; Lee, Wee Siang Vincent; Xue, Junmin textito-Benzenediol-Functionalized Carbon Nanosheets as Low Self-Discharge Aqueous Supercapacitors Journal Article 30 CHEMSUSCHEM, 11 (18), pp. 3307-3314, 2018, ISSN: 1864-5631. @article{ISI:000445178400033, title = {textito-Benzenediol-Functionalized Carbon Nanosheets as Low Self-Discharge Aqueous Supercapacitors}, author = {Ting Xiong and Zhi Gen Yu and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1002/cssc.201801076}, times_cited = {30}, issn = {1864-5631}, year = {2018}, date = {2018-09-21}, journal = {CHEMSUSCHEM}, volume = {11}, number = {18}, pages = {3307-3314}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Widening the voltage window is often proposed as a way to increase the energy density of aqueous supercapacitors. However, attempting to operate beyond the aqueous supercapacitor stability region can undermine the supercapacitor reliability due to pronounced electrolyte decomposition, which can lead to a significant self-discharge process. To minimize this challenge, charge injection by grafting o-benzenediol onto the carbon electrode is proposed through a simple electrochemical cycling technique. Due to charge injection from o-benzenediol into the carbon electrode, the equilibrium potential of the individual electrode can be reduced. In addition, due to its small molecular size, charge distribution, which is commonly faced by bulk pseudocapacitive materials, is also avoided. The assembled supercapacitor based on the o-benzenediol-grafted carbon demonstrated a maximum energy density of 24Whkg(-1) and a maximum power density of 69kWkg(-1), with a retention of 89% after 10000cycles at 10Ag(-1). A low self-discharge of about 4h was recorded; this could be attributed to the low driving force arising from the lower equilibrium potential. Thus, the proposed technique may provide insight towards the tuning of the equilibrium potential to attain reliable, high-performing supercapacitors with a low self-discharge process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Widening the voltage window is often proposed as a way to increase the energy density of aqueous supercapacitors. However, attempting to operate beyond the aqueous supercapacitor stability region can undermine the supercapacitor reliability due to pronounced electrolyte decomposition, which can lead to a significant self-discharge process. To minimize this challenge, charge injection by grafting o-benzenediol onto the carbon electrode is proposed through a simple electrochemical cycling technique. Due to charge injection from o-benzenediol into the carbon electrode, the equilibrium potential of the individual electrode can be reduced. In addition, due to its small molecular size, charge distribution, which is commonly faced by bulk pseudocapacitive materials, is also avoided. The assembled supercapacitor based on the o-benzenediol-grafted carbon demonstrated a maximum energy density of 24Whkg(-1) and a maximum power density of 69kWkg(-1), with a retention of 89% after 10000cycles at 10Ag(-1). A low self-discharge of about 4h was recorded; this could be attributed to the low driving force arising from the lower equilibrium potential. Thus, the proposed technique may provide insight towards the tuning of the equilibrium potential to attain reliable, high-performing supercapacitors with a low self-discharge process. |
Lee, Wee Siang Vincent; Xiong, Ting; Loh, Guan Chee; Tan, Teck Leong; Xue, Junmin Optimizing Electrolyte Physiochemical Properties toward 2.8 V Aqueous Supercapacitor Journal Article 31 ACS APPLIED ENERGY MATERIALS, 1 (7), pp. 3070-3076, 2018, ISSN: 2574-0962. @article{ISI:000458706000011, title = {Optimizing Electrolyte Physiochemical Properties toward 2.8 V Aqueous Supercapacitor}, author = {Wee Siang Vincent Lee and Ting Xiong and Guan Chee Loh and Teck Leong Tan and Junmin Xue}, doi = {10.1021/acsaem.8b00751}, times_cited = {31}, issn = {2574-0962}, year = {2018}, date = {2018-07-01}, journal = {ACS APPLIED ENERGY MATERIALS}, volume = {1}, number = {7}, pages = {3070-3076}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Achieving a wide potential window of aqueous supercapacitor has been one of the key research interests to address its poor energy density. However, in this process, water decomposition becomes an increasingly significant issue that has to be tackled in order to attain a reliable aqueous supercapacitor. In order to avoid possible water decomposition at a wide potential, benign interaction between electrolyte and electrode during the cell operation has to be considered. In this work, a water-in-bisalt electrolyte consisting of 21 M lithium bis(trifluoromethane)-sulfonamide and 1 M lithium sulfate was proposed. To complement the electrolyte, Li+ inserted MnO2 and carbon were selected as electrode materials due to their low oxygen evolution reaction/hydrogen evolution reaction activities. The resultant aqueous supercapacitor was able to operate at 2.8 V which, to the best of our knowledge, is one of the widest potential windows reported for an aqueous supercapacitor system. The cell was able to deliver an energy density of 55.7 Wh kg(-1) at power density of 1 kW kg(-1), while attaining a good cyclic stability of 84.6% retention after 10000 cycles at a current density of 30 A g(-1). Such a strategy may be effective in the design of wide potential aqueous supercapacitors, which is crucial toward future supercapacitor development.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Achieving a wide potential window of aqueous supercapacitor has been one of the key research interests to address its poor energy density. However, in this process, water decomposition becomes an increasingly significant issue that has to be tackled in order to attain a reliable aqueous supercapacitor. In order to avoid possible water decomposition at a wide potential, benign interaction between electrolyte and electrode during the cell operation has to be considered. In this work, a water-in-bisalt electrolyte consisting of 21 M lithium bis(trifluoromethane)-sulfonamide and 1 M lithium sulfate was proposed. To complement the electrolyte, Li+ inserted MnO2 and carbon were selected as electrode materials due to their low oxygen evolution reaction/hydrogen evolution reaction activities. The resultant aqueous supercapacitor was able to operate at 2.8 V which, to the best of our knowledge, is one of the widest potential windows reported for an aqueous supercapacitor system. The cell was able to deliver an energy density of 55.7 Wh kg(-1) at power density of 1 kW kg(-1), while attaining a good cyclic stability of 84.6% retention after 10000 cycles at a current density of 30 A g(-1). Such a strategy may be effective in the design of wide potential aqueous supercapacitors, which is crucial toward future supercapacitor development. |
Xiong, Ting; Tan, Teck Leong; Lu, Li; Lee, Wee Siang Vincent; Xue, Junmin Harmonizing Energy and Power Density toward 2.7 V Asymmetric Aqueous Supercapacitor Journal Article 215 ADVANCED ENERGY MATERIALS, 8 (14), 2018, ISSN: 1614-6832. @article{ISI:000435713600022, title = {Harmonizing Energy and Power Density toward 2.7 V Asymmetric Aqueous Supercapacitor}, author = {Ting Xiong and Teck Leong Tan and Li Lu and Wee Siang Vincent Lee and Junmin Xue}, doi = {10.1002/aenm.201702630}, times_cited = {215}, issn = {1614-6832}, year = {2018}, date = {2018-05-15}, journal = {ADVANCED ENERGY MATERIALS}, volume = {8}, number = {14}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Tremendous research efforts are devoted to developing wide potential window aqueous supercapacitors to resolve their low energy density concern. While the operational potential window is dictated by the intrinsic electrochemical stability of water (1.23 V), such a bottleneck may be surpassed by leveraging the additional overpotential of the oxygen evolution reaction and the hydrogen evolution reaction (HER). Herein, by employing an electroreduction technique, Na+ is adsorbed onto the carbon negative electrode which effectively acts as a physical barrier to hinder intermediate HER product formation, thereby reducing HER activity. To complement the wide potential carbon electrode, Na0.25MnO2 is employed as the positive electrode to take advantage of the extra energy (i.e., increased overpotential) required for Na+ insertion process into the structure. The asymmetric supercapacitor exhibits high energy density of 61.1 W h kg(-1) at a power density of 982 W kg(-1), and even at an ultrahigh power density of 42.9 kW kg(-1), a respectable energy density of 16.3 W h kg(-1) is attained. In addition, 93.7% capacitance retention is recorded after cycling for 10 000 cycles which further demonstrates its suitability as supercapacitor. The present success in fabricating a 2.7 V asymmetric supercapacitor will open a promising research route toward achieving high energy density and high power density.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Tremendous research efforts are devoted to developing wide potential window aqueous supercapacitors to resolve their low energy density concern. While the operational potential window is dictated by the intrinsic electrochemical stability of water (1.23 V), such a bottleneck may be surpassed by leveraging the additional overpotential of the oxygen evolution reaction and the hydrogen evolution reaction (HER). Herein, by employing an electroreduction technique, Na+ is adsorbed onto the carbon negative electrode which effectively acts as a physical barrier to hinder intermediate HER product formation, thereby reducing HER activity. To complement the wide potential carbon electrode, Na0.25MnO2 is employed as the positive electrode to take advantage of the extra energy (i.e., increased overpotential) required for Na+ insertion process into the structure. The asymmetric supercapacitor exhibits high energy density of 61.1 W h kg(-1) at a power density of 982 W kg(-1), and even at an ultrahigh power density of 42.9 kW kg(-1), a respectable energy density of 16.3 W h kg(-1) is attained. In addition, 93.7% capacitance retention is recorded after cycling for 10 000 cycles which further demonstrates its suitability as supercapacitor. The present success in fabricating a 2.7 V asymmetric supercapacitor will open a promising research route toward achieving high energy density and high power density. |