Kang Fulian, Li Yang, Zheng Zhiyuan, Peng Xinya, Rong Jianhua, Dong Liubing
College of Chemistry and Materials Science, Jinan University, Guangzhou 511443, China.
Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
J Colloid Interface Sci. 2024 Sep;669:766-774. doi: 10.1016/j.jcis.2024.05.048. Epub 2024 May 9.
Aqueous Zn-ion hybrid supercapacitors (ZHSs) are attracting significant attention as a promising electrochemical energy storage system. However, carbon cathodes of ZHSs exhibit unsatisfactory ion storage performance due to the large size of hydrated Zn-ions (e.g., [Zn(HO)]), which encumbers compact ion arrangement and rapid ion transport at the carbon-electrolyte interfaces. Herein, a porous carbon material (HMFC) with abundant sub-nanopores is synthesized to optimize the ion storage performance of the carbon cathode in ZHSs, in which the sub-nanopores effectively promote the dehydration of hydrated Zn-ions and thus optimize the ion storage performance of the carbon cathode in ZHSs. A novel strategy is proposed to study the dehydration behaviors of hydrated Zn-ions in carbon cathodes, including quantitatively determining the desolvation activation energy of hydrated Zn-ions and in-situ monitoring active water content at the carbon-electrolyte interface. The sub-nanopores-induced desolvation effect is verified, and its coupling with large specific surface area and hierarchically porous structure endows the HMFC cathode with improved electrochemical performance, including a 53 % capacity increase compared to the carbon cathode counterpart without sub-nanopores, fast charge/discharge ability that can output 46.0 Wh/kg energy within only 4.4 s, and 98.2 % capacity retention over 20,000 charge/discharge cycles. This work provides new insights into the rational design of porous carbon cathode materials toward high-performance ZHSs.
水系锌离子混合超级电容器（ZHSs）作为一种很有前景的电化学储能系统正受到广泛关注。然而，ZHSs的碳阴极由于水合锌离子（如[Zn(HO)]）尺寸较大，在碳-电解质界面阻碍了紧密的离子排列和快速的离子传输，导致离子存储性能不尽人意。在此，合成了一种具有丰富亚纳米孔的多孔碳材料（HMFC），以优化ZHSs中碳阴极的离子存储性能，其中亚纳米孔有效地促进了水合锌离子的脱水，从而优化了ZHSs中碳阴极的离子存储性能。提出了一种新策略来研究碳阴极中水合锌离子的脱水行为，包括定量测定水合锌离子的去溶剂化活化能和原位监测碳-电解质界面的活性水含量。验证了亚纳米孔诱导的去溶剂化效应，其与大比表面积和分级多孔结构的耦合赋予了HMFC阴极更好的电化学性能，包括与没有亚纳米孔的碳阴极相比容量增加53%，快速充放电能力在仅4.4秒内就能输出46.0 Wh/kg的能量，以及在20000次充放电循环中容量保持率为98.2%。这项工作为高性能ZHSs的多孔碳阴极材料的合理设计提供了新的见解。
