Browsing by Author "Yang, Jianhong"

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    High performance rechargeable aluminium ion batteries enabled by full utilization and understanding of polyaniline cathodes
    (Elsevier, 2024-07-08) Wei, Guokang; Qiao, Jia; Li, Xin; Tao, Fei; Xue, Weixi; Hu, Sijiang; Luo, Zhenhua; Yang, Jianhong
    As a renowned conductive polymer, polyaniline (PANI) shows remarkable potential in organic cathode materials for rechargeable aluminium ion batteries (RAIBs). However, existing research has not given sufficient understanding and explanation of the structure and states of PANI but failed to achieve ideal electrochemical performance. In this study, we differentiate and investigate for the first time its primary-doped (PANI-1), re-doped (PANI-Re), secondary-doped (PANI-2), and emeraldine based (PANI-EB) forms, meanwhile attempt to enhance the conductivity of PANI-EB using multi-walled carbon nanotubes (PANI-EB@C). Among them, the high-doped PANI-2 and non-doped PANI-EB exhibit theoretical capacity utilization far superior to lower doped PANI-1 and PANI-Re, with both specific capacities reaching approximately 225 mAh/g (full capacity utilization rate of 76.53 %) at a current density of 1 A/g, while maintaining capacity retention rates of 92.89 % after 2000 cycles and 92.44 % after 5000 cycles, respectively. Furthermore, the high-conductivity PANI-EB@C displays a discharge specific capacity of 284 mAh/g (full capacity utilization rate of 96.59 %), with a capacity retention rate of 91.19 % after 5000 cycles. Electrochemical analysis, Gaussian theoretical calculations, ex-situ characterization collectively indicate that the electrochemical performance of doped PANI is positively correlated with the degree of doping-induced conductivity changes, while the unique internal redox process of PANI-EB enhances the release of performance and could be further optimized by the assistant of conductivity medium. This work advances the classification of the electrochemical performance and structural understanding of PANI cathode materials to an extremely high stage, towards the practical application of a low-cost, high-performance, sustainable, and green cathode material in large-scale energy storage devices.
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    High performance rechargeable aluminium ion batteries enabled by strategy of covalent organic frame material
    (Elsevier, 2025-05-01) Wei, Guokang; Qiao, Jia; Li, Xin; Dou, Aichun; Hu, Sijiang; Xie, Wei; Luo, Zhenhua; Yang, Jianhong
    Emerging rechargeable aluminium-ion batteries (RAIBs) are a sustainable option for the next generation of low-cost, high-safety and large-scale energy storage technologies. While the unsatisfying availability of traditional inorganic materials has limited the development of RAIBs, the advance of organic materials is expected to be a breakthrough towards high-performance cathode. However, the existing extensive research often focuses on the selection of appropriate organic monomers or stay in the tentative stage of preliminary polymerization. It is difficult to break through the inherent characteristics of the instability of small organic ones and the easy aggregation and accumulation of macromolecular polymers, which is no doubt ignoring the huge potential of organic compounds for structural design at the molecular level. In this connection, our study demonstrates a material design strategy that introduces active functional groups to small molecular monomers and polymerizes them into REDOX active covalent organic framework (COF) with multiple N-containing groups. Theoretical simulations and ex-situ analysis revealed the key function of C-N and C=N as active sites for reversible storage of AlCl2 + ions. In addition, the macro-ring frame brings enhanced structural stability and environmental tolerance for COF in complex electrolyte, resulting in significantly improved electrochemical performance. At 1 A g−1, it exhibits a high specific capacity of 161.2 mAh g−1 and an excellent cycle life of approximately 100 % coulombic efficiency after more than 3,000 cycles. This work fully demonstrates the operability of the design strategy to synthesize COF from small molecular organics by introducing reactive functional groups and its great potential in the role of cathode materials in RAIBs. The success meanwhile provides an inspiration for the development of COF-based organic battery system in large-scale energy storage.
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    Spatial reticulate polytriphenylamine cathode material with enhanced capacity for rechargeable aluminum ion batteries
    (Springer, 2023-07-03) Tao, Fei; Wei, Guokang; Xu, Xinqi; Xu, Weize; Xie, Wei; Yang, Jianhong; Luo, Zhenhua; Li, Xin; Qiao, Jia
    Rechargeable aluminum ion batteries (RAIBs) are a very attractive option for large-scale energy storage thanks to their promising theoretical capacity, high energy density, low cost, abundant earth resources, and environmental friendliness. While the cathode materials chosen and prepared are so essential for the electrochemical performance of RAIBs that extensive efforts and research have been done. In this study, the electrochemical performances of RAIBs were optimally improved by the chemical polymerization of triphenylamine to obtain polytriphenylamine (PTPAn) as the cathode material. The polymerization process improved the spatial reticulate structure of triphenylamine, gained a three-dimensional mesh-like nanostructure, which provided more chemical reaction sites and ion reaction channels, greatly increased the specific surface area, and accelerated the electrochemical reaction kinetics. On this basis, a stable discharge-specific capacity of around 137.4 mAh g−1 was achieved at high current densities of 1 A g−1 for the PTPAn cathode, and the Coulombic efficiency was maintained at about 99% after the life of 500 cycles. The understanding and appreciation of the charging and discharging working principle of PTPAn material as RAIBs cathode, meantime, were deepened by a multitude of ex-situ experiments. These findings are anticipated to serve as the cornerstone for the subsequent development of large-scale RAIBs systems for energy storage that use organic polymers as the cathode material.