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Achieving Insertion‐Like Capacity at Ultrahigh Rate via Tunable Surface Pseudocapacitance
Advanced Materials ( IF 27.4 ) Pub Date : 2018-02-09 , DOI: 10.1002/adma.201706640 Teng Zhai 1 , Shuo Sun 1 , Xiaojing Liu 2 , Chaolun Liang 3 , Gongming Wang 2 , Hui Xia 1
Advanced Materials ( IF 27.4 ) Pub Date : 2018-02-09 , DOI: 10.1002/adma.201706640 Teng Zhai 1 , Shuo Sun 1 , Xiaojing Liu 2 , Chaolun Liang 3 , Gongming Wang 2 , Hui Xia 1
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The insertion/deinsertion mechanism enables plenty of charge‐storage sites in the bulk phase to be accessible to intercalated ions, giving rise to at least one more order of magnitude higher energy density than the adsorption/desorption mechanism. However, the sluggish ion diffusion in the bulk phase leads to several orders of magnitude slower charge‐transport kinetics. An ideal energy‐storage device should possess high power density and large energy density simultaneously. Herein, surface‐modified Fe2O3 quantum dots anchored on graphene nanosheets are developed and exhibit greatly enhanced pseudocapacitance via fast dual‐ion‐involved redox reactions with both large specific capacity and fast charge/discharge capability. By using an aqueous Na2SO3 electrolyte, the oxygen‐vacancy‐tuned Fe2O3 surface greatly enhances the absorption of SO32− anions that majorly increase the surface pseudocapacitance. Significantly, the Fe2O3‐based electrode delivers a high specific capacity of 749 C g−1 at 5 mV s−1 and retains 290 C g−1 at an ultrahigh scan rate of 3.2 V s−1. With a novel dual‐electrolyte design, a 2 V Fe2O3/Na2SO3//MnO2/Na2SO4 asymmetric supercapacitor is constructed, delivering a high energy density of 75 W h kg−1 at a power density of 3125 W kg−1.
中文翻译：
通过可调表面伪电容以超高速率实现类似插入的容量
插入/去插入机制使本体相中的大量电荷存储位点可被插入的离子访问，从而使能量密度比吸附/解吸机制高出至少一个数量级。但是，整体相中缓慢的离子扩散会导致电荷传输动力学变慢几个数量级。理想的储能设备应同时具有高功率密度和大能量密度。本文研究了锚固在石墨烯纳米片上的表面修饰的Fe 2 O 3量子点，并通过具有大比容量和快速充电/放电能力的快速双离子参与的氧化还原反应显示出大大增强的伪电容。通过使用Na 2 SO水溶液3电解质，经过氧空位调整的Fe 2 O 3表面大大增强了SO 3 2-阴离子的吸收，从而大大增加了表面假电容。显著的Fe 2 ö 3系电极提供的749 C g还高比容量-1以5mV小号-1并保持290℃克-1以3.2 Vs的超高扫描速率-1。采用新颖的双电解质设计，2 V Fe 2 O 3 / Na 2 SO 3 // MnO 2 / Na 2 SO 4构造非对称超级电容器，以3125 W kg -1的功率密度提供75 W h kg -1的高能量密度。
更新日期：2018-02-09
中文翻译：
通过可调表面伪电容以超高速率实现类似插入的容量
插入/去插入机制使本体相中的大量电荷存储位点可被插入的离子访问，从而使能量密度比吸附/解吸机制高出至少一个数量级。但是，整体相中缓慢的离子扩散会导致电荷传输动力学变慢几个数量级。理想的储能设备应同时具有高功率密度和大能量密度。本文研究了锚固在石墨烯纳米片上的表面修饰的Fe 2 O 3量子点，并通过具有大比容量和快速充电/放电能力的快速双离子参与的氧化还原反应显示出大大增强的伪电容。通过使用Na 2 SO水溶液3电解质，经过氧空位调整的Fe 2 O 3表面大大增强了SO 3 2-阴离子的吸收，从而大大增加了表面假电容。显著的Fe 2 ö 3系电极提供的749 C g还高比容量-1以5mV小号-1并保持290℃克-1以3.2 Vs的超高扫描速率-1。采用新颖的双电解质设计，2 V Fe 2 O 3 / Na 2 SO 3 // MnO 2 / Na 2 SO 4构造非对称超级电容器，以3125 W kg -1的功率密度提供75 W h kg -1的高能量密度。
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