正极材料钒酸钾的可控制备及其电化学储锌性能  

Controllable preparation and electrochemical zinc⁃storage properties of potassium vanadate as cathode material

作　　者：黄鑫权 卢超 HUANG Xinquan;LU Chao(School of Mechanical Engineering,Chengdu University,Chengdu 610106,China)

机构地区：[1]成都大学机械工程学院,四川成都610106

出　　处：《中国有色冶金》2024年第5期40-46,共7页China Nonferrous Metallurgy

基　　金：云南省高校怒江河谷生物质资源高值转化与利用实验室开放基金(Z386);成都大学人才工程科研启动项目(2081921012)。

摘　　要：K_(x)V_(2)O_(5)材料具有优异的电化学性能,可作为水系锌离子电池的优良正极材料,该材料的可控合成至关重要。本研究探讨水热法过程中草酸(C_(2)H_(2)O_(4)·2H_(2)O)和五氧化二钒(V2O5)的物质的量比对材料的结构、形貌及电化学性能的影响规律,实现了钒酸钾(K_(0.486)V_(2)O_(5))的可控制备。研究结果表明,当C_(2)H_(2)O_(4)·2H_(2)O/V2O5的物质的量比约为5∶2时,钒酸钾具有较高的结晶度和更规整的纳米棒状形貌,显著的赝电容效应赋予其卓越的倍率性能和优异的动力学特性,展现出高容量及良好的循环稳定性,在0.1、0.2、0.5、1、2、5和10 A·g^(-1)电流密度下,放电比容量分别为395.3、366.9、323.4、283.5、247.7、181.8和127.3 mAh·g^(-1),在5 A·g^(-1)的大电流密度下循环2000圈的可逆容量仍保留196.5 mAh·g^(-1),容量保持率达127.9%。K0.486V2O5的电化学储能过程由离子扩散过程和表面电容行为共同控制,随着扫描速率增大,Zn2+的存储主要受电容行为控制,显著的赝电容效应是材料获得卓越倍率性能和优异电化学反应动力学的关键因素。K_(x)V_(2)O_(5)with excellent electrochemical properties can be used as an excellent cathode material for aqueous zinc⁃ion batteries,and its controllable synthesisis especially important.In this study,the effects of the molar ratio of oxalic acid(C_(2)H_(2)O_(4)·2H_(2)O)to vanadium pentoxide(V2 O5)on the structure,morphology and electrochemical properties of potassium vanadate(K_(0.486)V_(2)O_(5))cathodes were investigated.The controllable preparation of K0.486 V2 O5 was achieved.The results show that when the molar ratio of C_(2)H_(2)O_(4)·2H_(2)O/V2 O5 is about 5∶2,potassium vanadate has higher crystallinityandmore regularnanorod⁃likemorphology.The distinct pseudocapacitive effect endows it with excellent rate performance and outstanding kinetic characteristics,showing high capacity and good cycling stability.At current densities of 0.1,0.2,0.5,1,2,5 and 10 A·g^(-1),the discharge specific capacities are 395.3,366.9,323.4,283.5,247.7,181.8 and 127.3 mAh·g^(-1),respectively.At a high current density of 5 A·g^(-1),it still delivers a reversible capacity of 196.5 mAh·g^(-1)after 2000 cycles with an ultrahigh capacity retention rate of 127.9%.The energy storage process of K0.486 V2 O5 is controlled by ion diffusion process and surface capacitance behavior.With the increase of the scanning rate,the storage of Zn2+is mainly controlled by the capacitive behavior.The significant pseudocapacitance effect is the key factor to obtaining excellent rate performance and eminentkinetic behavior.

关 键 词：水系锌离子电池 正极材料 钒酸钾 电化学性能 赝电容效应 

分 类 号：TM911[电气工程—电力电子与电力传动]