KMn8O16纳米纤维微球及其水系锌离子电池性能研究

Preparation and electrochemical performances of KMn_(8)O_(16) nanofiber microspheres and related aqueous zinc-ion battery

电池在充放电过程中,锰基材料会发生材料体积膨胀、锰的溶解、锌的腐蚀以及水的分解等副反应,从而减少电池使用寿命。为抑制二氧化锰体积膨胀,通过一步水热反应合成了由纳米纤维组成的微球嵌钾化合物(KMn_(8)O_(16))。结果表明,在3 mol/L ZnSO_(4)和0.1 mol/L MnSO_(4)组成的电解液中加入40%(体积分数)的乙二醇(EG),能一定程度上抑制析氢副反应,同时,EG可以作为低温电解液使用。KMn_(8)O_(16)纳米纤维微球作为锌离子电池正极材料表现出优异的倍率性能和高的比容量。电流密度为200 mA/g时,经过100次循环,容量约为200 mA·h/g,即使在1000 mA/g大电流密度下循环200次,容量仍能达到150 mA·h/g。

During the charging and discharging of battery,Mn-based materials may suffer side reactions,including the expansion of volume,the dissolution of Mn,the corrosion of Zn and the decomposition of water,which will shorten the service life of battery.In order to restrain the expansion of volume of MnO_(2),an intercalated potassium compound(KMn_(8)O_(16))microsphere formed with nanofiber is prepared via one-step hydrothermal reaction.It is found that adding 40%(volume fraction)ethylene glycol(EG)to the electrolyte composed of 3 M ZnSO_(4) and 0.1 M MnSO_(4) can inhibit the hydrogen evolution side reaction.Moreover,EG can also be used as low-temperature electrolytes.When KMn_(8)O_(16) microsphere is used as cathode material for zinc-ion batteries,it shows good rate performance and high specific capacity.The current capacity of the batter can deliver 200 mA h·g^(-1) after 100 cycles at a current density of 200 mA·g^(-1).The current capacity of the battery can still deliver 150 mA h·g^(-1) after 200 cycles at a current density of 1000 mA·g^(-1).