超级电容器
材料科学
石墨烯
电容
电解质
氧化物
水平扫描速率
纳米技术
电极
电化学
化学工程
循环伏安法
工程类
物理化学
化学
冶金
作者
Jun Yan,Chang E. Ren,Kathleen Maleski,Christine B. Hatter,Babak Anasori,Patrick Urbankowski,Asya Sarycheva,Yury Gogotsi
标识
DOI:10.1002/adfm.201701264
摘要
A strategy to prepare flexible and conductive MXene/graphene (reduced graphene oxide, rGO) supercapacitor electrodes by using electrostatic self‐assembly between positively charged rGO modified with poly(diallyldimethylammonium chloride) and negatively charged titanium carbide MXene nanosheets is presented. After electrostatic assembly, rGO nanosheets are inserted in‐between MXene layers. As a result, the self‐restacking of MXene nanosheets is effectively prevented, leading to a considerably increased interlayer spacing. Accelerated diffusion of electrolyte ions enables more electroactive sites to become accessible. The freestanding MXene/rGO‐5 wt% electrode displays a volumetric capacitance of 1040 F cm −3 at a scan rate of 2 mV s −1 , an impressive rate capability with 61% capacitance retention at 1 V s −1 and long cycle life. Moreover, the fabricated binder‐free symmetric supercapacitor shows an ultrahigh volumetric energy density of 32.6 Wh L −1 , which is among the highest values reported for carbon and MXene based materials in aqueous electrolytes. This work provides fundamental insight into the effect of interlayer spacing on the electrochemical performance of 2D hybrid materials and sheds light on the design of next‐generation flexible, portable and highly integrated supercapacitors with high volumetric and rate performances.
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