优化炭表面氧官能团增强锌离子电容器的电容性能  

Optimizing oxygen substituents of a carbon cathode for improved capacitive behavior in ethanol-based zinc-ion capacitors

作　　者：袁平 肖浩鸣 李均益 罗俊辉 罗先游 陈大明[1] 李德[1] 陈永[1,2] YUAN Ping;XIAO Hao-ming;LI Jun-yi;LUO Jun-hui;LUO Xian-you;CHEN Da-ming;LI De;CHEN Yong(State Key Laboratory of Marine Resource Utilization in South China Sea,Hainan Provincial Key Laboratory of Research on Utilization of Si-Zr-Ti Resources,Hainan University,Haikou 570228,China;Guangdong Key Laboratory for Hydrogen Energy Technologies,School of Materials Science and Hydrogen Energy,Foshan University,Foshan 528000,China)

机构地区：[1]海南大学材料科学与工程学院,海南省硅锆钛资源利用研究重点实验室,南海海洋资源利用国家重点实验室,海南海口570228 [2]佛山科学技术学院材料科学与氢能学院,广东省氢能技术重点实验室,广东佛山528000

出　　处：《新型炭材料（中英文）》2023年第3期522-533,共12页New Carbon Materials

基　　金：国家自然科学基金(52062012);广东省重点学科建设项目(2021ZDJS102);广东省高校创新团队(2022KCXTD030、2020KCXTD011);广东大学生科技创新培育专项资金(pdjh2023b0549);佛山科学技术学院学术基金(xsjj202206kjb02).

摘　　要：锌离子电容器(ZICs)具有能量密度高、倍率性能好、循环寿命长、成本低等优点,近年来得到了广泛的研究。在碳基阴极表面引入氧官能团是提高水系ZICs电容性能的有效策略。然而,氧官能团的存在是否有利于提高乙醇(EtOH)基ZICs的电容性能,目前还没有被深入研究。本文采用硝酸氧化和进一步热处理的方法对阴极活性炭表面的氧官能团进行了优化。在ZnCl2/EtOH电解液中,优化后的样品在电流密度为1 A g^(−1)时比电容达到195 F g^(−1),比未改性的样品(125 F g^(−1))提高了56%。同时,ZICs也表现出良好的循环稳定性,在3 A g^(−1)下的稳定循环次数超过16000次,并且保持100%的库仑效率。这是因为氧官能团,特别是羧基和酯基(―COO)的存在,为Zn2+氧化还原反应提供了丰富的电化学活性位点。因此,本研究通过优化氧官能团增强了炭阴极的电容性能,并为EtOH基ZICs的商业应用提供了研究基础。Zinc ion capacitors(ZICs)have been widely studied in recent years due to their high energy density,excellent rate capability,long cycling life and low cost.The incorporation of oxygen functional groups(OFGs)on the surface of the carbon-based cathodes is an effective strategy for improving the capacitive performance of aqueous ZICs.However,whether their presence helps improve the capacitance of ethanol(EtOH)-based ZICs has not been investigated.In this work,a combination of nitric acid oxidation and thermal treatment was used to regulate the OFGs on the activated surface of the carbon cathode.The optimized sample had a high specific capacitance of 195 F g^(−1) at 1 A g^(−1) using ZnCl2/EtOH as the electrolyte,i.e.,a 56%increase compared to an unmodified cathode(125 F g^(−1)).ZICs also shown excellent stability for more than 16000 cycles at 3 A g^(−1),while maintaining 100%coulombic efficiency.This significantly improved performance is attributed to the presence of OFGs,especially carboxyl and ester groups,which provide abundant electrochemical active sites for redox reaction with the zinc ions.This study reports a significant improvement in the specific capacitance of carbon cathodes for commercial EtOH-based ZIC systems.

关 键 词：锌离子电容器 氧官能团 乙醇 活性炭 比电容 

分 类 号：TQ127.11[化学工程—无机化工]