摘要
研究了水系电解液中Li^+、Zn^(2+)和Mn^(2+)阳离子对具有不同晶型结构和形貌的MnO_2正极电化学性能的影响,探讨其储能机理。结果表明,在不含Mn(Ⅱ)离子的水溶液中,MnO_2电极所表现的电化学性能趋同,容量低,衰减快。含有Zn^(2+)离子的水溶液中,MnO_2电极因二价锌离子的嵌入-脱出,容量明显提升,但衰减严重。当溶液中同时含有Zn^(2+)、Mn^(2+)离子时,基于Mn^(2+)和Zn^(2+)离子之间的协同作用和Mn^(2+)离子氧化/还原反应过程的作用,有效抑制MnO_2颗粒的聚集和结构塌陷,削弱碱式硫酸锌杂质不利的影响,保持了锌离子在MnO_2电极中嵌入-脱出的高容量特性(200 m Ah?g^(-1),电流密度:100m A?g^(-1)),及良好的循环稳定性。
The effect of Li^＋, Zn^2＋, and MR^2＋ ions in aqueous solution on the electrochemical performance of the MnO2 cathode characterized by different crystal structures and morphologies was investigated. The energy storage mechanism of MnO2 in the mixed solution was probed. The results show that in aqueous solution without Mn^2＋ ions, various MnO2 electrodes exhibit similar electrochemical performance with low capacity and severe attenuation. In an aqueous solution with Zn^2＋ ions, the capacity of MnO2 electrodes is enhanced, which can be attributed to insertion/extraction of zinc ions, However, the decay of the capacity is drastic. When aqueous solutions containing Mn^2＋ and Zn2. ions are used, particle aggregation and crystal structure collapse of MnO2 are effectively prevented owing to the synergistic effect of zinc and manganese ions and the redox reaction process of Mn^2＋ ions. The negative influence of the ZnSO4·3Zn（OH）2 impurity is also weakened. As a result, the high capacity of MnO2 electrodes resulting from insertion/extraction of zinc ions is maintained （-200 mAh·g^-1 at 100 mA·g^-1） with excellent cycling stability.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2016年第8期2007-2017,共11页
Acta Physico-Chimica Sinica
基金
先进化学蓄电技术与材料北京市重点实验室项目(Z121109002812019)资助~~
关键词
水系可充电池
MNO2
电解液
锌锰离子存储
Aqueous rechargeable battery
Manganese dioxide
Electrolyte
Zincand manganese ionstorage
作者简介
Corresponding authors. WEN Yue-Hua, Email：wen yuehua@126.com; Tel： ＋86-10-66748543.
LI Dian-Qing, Email： lidq@mail.buct.edu.cn.
