V_(2)O_(5)@rGO纳米材料的制备及其在水系锌离子电池中的应用

Preparation of V_(2)O_(5)@rGO Nanomaterials and Their Application in Aqueous Zinc-Ion Batteries

V_(2)O_(5)作为水系锌离子电池(ZIB)的正极材料具有很大的潜力,但在高电流密度下稳定性和导电性较差。为了改善其充放电性能,制备了一种由还原氧化石墨烯(rGO)和V_(2)O_(5)组成的V_(2)O_(5)@rGO复合材料。利用简单溶剂热法,碳包覆的V_(2)O_(5)颗粒成功生长在rGO表面。使用扫描电子显微镜(SEM)观察到,V_(2)O_(5)颗粒较为均匀地分布在rGO两侧,有助于锌离子的插入/脱出。电化学测试结果表明,在电流密度为7 A·g^(-1)时,V_(2)O_(5)@rGO电极的放电比容量为166.7 mA·h·g^(-1),高于V_(2)O_(5)电极的放电比容量(72.7 mA·h·g^(-1))。在5 A·g^(-1)电流密度下,V_(2)O_(5)@rGO电极循环500次后,其放电比容量为82.5 mA·h·g^(-1),容量保持率为92.8%,证明V_(2)O_(5)@rGO电极比V_(2)O_(5)电极具有更突出的循环稳定性和高导电性。

As a cathode material for aqueous zinc-ion batteries(ZIBs),V_(2)O_(5)has great potential,but its stability and conductivity are poor at high current density.To improve its chargedischarge performances,a V_(2)O_(5)@reduced graphene oxide(rGO)composite consisting of V_(2)O_(5)and rGO was prepared.By a simple solvothermal method,carbon-coated V_(2)O_(5)particles were successfully grown on the rGO surface.And by scanning electron microscope,it is observed that the particles were evenly distributed on both sides of rGO,facilitating insertion/removal of zinc ions.Electrochemical testing results show that the discharge specific capacity of the V_(2)O_(5)@rGO electrode is 166.7 mA·h·g^(-1)at 7 A·g^(-1)current density,which is higher than that(72.7 mA·h·g^(-1))of the V_(2)O_(5)electrode.After 500 cycles of the V_(2)O_(5)@rGO electrode at 5 A·g^(-1)current density,the discharge specific capacity is 82.5 mA·h·g^(-1)and the capacity retention rate is 92.8%,proving that V_(2)O_(5)@rGO electrode has more outstanding cycle stability and high conductivity than V_(2)O_(5)electrode.