Linli Zhu

Bio: Linli Zhu is an academic researcher from Jiangsu University. The author has contributed to research in topics: Supercapacitor & Ternary operation. The author has an hindex of 6, co-authored 15 publications receiving 241 citations.

In situ growth of ZIF-8-derived ternary ZnO/ZnCo2O4/NiO for high performance asymmetric supercapacitors.

Abstract: In this paper, the rational design and synthesis of ZIF-8-derived ternary ZnO/ZnCo2O4/NiO wrapped by nanosheets is introduced. Polyhedral ternary ZnO/ZnCo2O4/NiO composites surrounded by nanosheets with different compositions are successfully fabricated through in situ growth on ZIF-8 templates and subsequent thermal annealing in air. Electrochemical investigation reveals that when the molar ratio of nickel nitrate to cobalt nitrate is 1, the composite material is more outstanding, which shows a high specific capacitance of 1136.4 F g-1 at 1 A g-1 and excellent cycling stability of 86.54% after 5000 cycles. Moreover, the excellent performance of this material is also confirmed by assembling an asymmetric supercapacitor. The assembled hybrid device can reach a large potential range of 0-1.6 V and deliver a high energy density of 46.04 W h kg-1 as well as the maximum power density of 7987.5 W kg-1.

Fluffy Cotton-Like GO/Zn–Co–Ni Layered Double Hydroxides Form from a Sacrificed Template GO/ZIF-8 for High Performance Asymmetric Supercapacitors

Abstract: The combination of carbon materials and active metal materials can prepare newly fashioned and hierarchical porous materials. Meanwhile, the combined action of the two materials can effectively opt...

Chemical supercapacitors: a review focusing on metallic compounds and conducting polymers

Abstract: Capacitors began their journey in 1745, and to date have advanced in the form of supercapacitors. Supercapacitors are one of the advanced forms of capacitors with higher energy density, bridging capacitors and batteries. The energy storage through the formation of an electrical double layer is pivotal for supercapacitor technology. Accordingly, to further improve the energy density, surface faradaic (pseudocapacitive) processes are employed, and henceforth, the journey of chemical supercapacitors commenced. Herein, the materials, mechanisms and fabrication of chemical supercapacitors based on metallic compounds and conducting polymers are discussed in detail. The inherent limitations of these materials are addressed, and the feasible mitigation measures are identified. Poor conductivity, slow diffusion kinetics and rapid structural disintegration over cycling are the common constraints of metallic compounds, which can be overcome by preparing conductive nanocomposites. Thus, versatile conductive nanocomposites of metal oxides, hydroxides, carbides, nitrides, phosphides, phosphates, phosphites, and chalcogenides are elaborated. A lack of structural integrity is the prime obstacle for the realization of conducting polymer-based supercapacitors, which may be solved by forming composites with robust support from carbonaceous materials or metallic compounds. Consequently, the composites of polyaniline, polypyrrole, polythiophene and polythiophene-derivatives are discussed. The historical accounts of early stages of works are emphasised in order to review the developmental pathways of chemical supercapacitors. The construction of full cells and their performance data are presented herein, which synchronize the behaviour of practical scaled-up devices. To the best of our knowledge, this review is the first holistic description of chemical supercapacitors based on metallic compounds and conducting polymers from the first reports to recent advancements.

High-Performance Hybrid Supercapacitor with 3D Hierarchical Porous Flower-like Layered Double Hydroxide Grown on Nickel Foam As Binder-Free Electrode

Abstract: The synthesis of layered double hydroxide (LDH) as electroactive material has been well reported; however, fabricating an LDH electrode with excellent electrochemical performance at high current density remains a challenge. In this paper, we report a 3D hierarchical porous flower-like NiAl-LDH grown on nickel foam (NF) through a liquid-phase deposition method as a high-performance binder-free electrode for energy storage. With large ion-accessible surface area as well as efficient electron and ion transport pathways, the prepared LDH-NF electrode achieves high specific capacity (1250 C g−1 at 2 A g−1 and 401 C g−1 at 50 A g−1) after 5000 cycles of activation at 20 A g−1 and high cycling stability (76.7% retention after another 5000 cycles at 50 A g−1), which is higher than those of most previously reported NiAl-LDH-based materials. Moreover, a hybrid supercapacitor with LDH-NF as the positive electrode and porous graphene nanosheet coated on NF (GNS-NF) as the negative electrode, delivers high energy density (30.2 Wh kg−1 at a power density of 800 W kg−1) and long cycle life, which outperforms the other devices reported in the literature. This study shows that the prepared LDH-NF electrode offers great potential in energy storage device applications.

Recent Advances of Asymmetric Supercapacitors

Abstract: Asymmetric supercapacitors (ASCs) have attracted significant attentions worldwide owing to their wider voltage window compared with symmetric supercapacitors (SCs). Through combinations of two electrodes with different charge storage mechanisms or different redox reactions, extended operating voltage window can be realized for ASCs. In this article, first the ASCs are classified into two types based on different charge storage mechanisms: electric double-layer capacitive (EDLC)//pseudocapacitive-type ASCs and EDLC// battery-type hybrid SCs. For the EDLC/pseudocapacitive-type ASC, carbon materials are adopted as anode and transition metal oxides including MnO2, RuO2, etc., are utilized as cathodes. For EDLC//battery-type hybrid SCs, carbon materials as anode are combined with metal oxide/hydroxide such as NiO, and Ni(OH)2, etc., as cathode. Recently, Li-ion-based ASCs composed of carbon materials and Li-ion battery-type electrode materials with a Li-containing organic electrolyte show great potentials to be promising alternatives. Some metal oxides/nitrides including InO2, Bi2O3, Fe3O4, Fe2O3, and VN can work in a negative potential range. By coupling another battery/pseudocapacitive electrode, all redox-type ASCs are assembled and their electrochemical performances are widely studied. Then, based on the above categories recent advances of ASCs are summarized. Finally, the challenges and prospects for the development of ASCs are pointed out from perspectives of this study.