物理化学学报2021，Vol.37Issue(3)：73-79,7.DOI:10.3866/PKU.WHXB201907049
NaOH浓度对Na0.44Mn02储钠性能的影响
Influence of NaOH Concentration on Sodium Storage Performance of Nao.44Mn02
摘要
Abstract
Aqueous sodium ion batteries(ASIBs)have attracted considerable attention for large-scale energy storage because of their prominent advantages of low cost,high safety,and environment-friendliness.Among the reported cathode materials for ASIBs,Nao.44Mn02 exhibits outstanding structural and hydrochemical stability,and hence is of much interest to research scholars.However,the reversible capacity of Nao.44Mn02 in most of the reported ASIBs was only 40 mAh·g-1 due to the restriction of stable working windows,although the in spite of theoretical capacity is121 mAh·g-1.Recently,we reported a Zn/Nao.44Mn02 dual-ion battery(AZMDIB)based on a Nao.44Mn02 positive electrode,Zn negative electrode,and 6 molL-1 NaOH electrolvte.The alkaline solution lowered the proton insertion potential and expanded the stable working window of the Nao.44Mn02 electrode,thus enhancing the reversible capacity to 80 mAh·g-1.Previous studies have demonstrated that the composition,concentration,and pH of the electrolytes have significant effects on the stable electrochemical window,rate performance,cycling performance,and other electrochemical properties of aqueous batteries.In addition,it has been reported that the co-intercalation of hydrogen ions can be inhibited by increasing the pH of the electrolyte in order to improve the cyclic stability of the electrode.Therefore,exploring the effect of electrolyte concentration and pH on the electrochemical performance of Nao.44Mn02 can provide insight into the design and optimization of high-performance Zn/Nao.44Mn02 aqueous batteries.Hence,in this work,rod-like Nao.44Mn02 was synthesized by ball milling and subsequent high-temperature calcination,and the influence of NaOH concentration on the electrochemical performance of the Nao.44Mn02 electrode was investigated by adopting five different concentrated electrolytes,1,3,6,8,and 10 mol-L-1 NaOH.The results showed that an increase in NaOH concentration is beneficial for preventing the insertion of protons and improving the cycling performance and the rate performance of the electrode;however,it also leads to premature triggering of the oxygen evolution reaction.Moreover,the rate performance would decrease at high NaOH concentration.The Nao.44Mn02 electrode showed optimal electrochemical performance in 8 mol-L-1 NaOH.At a current density of 0.5C(1C = 121 mA-g-1),a reversible specific capacity of 79.2 mAh·g-1 was obtained,and a capacity of 35.3 mAh·g-1 was maintained even at a high current density of 50C.In the potential window of 0.2-1.2 V(vs.NHE),the capacity retention after 500 weeks was 64.3％,which increased to 78.2％when the potential window was reduced to 0.25-1.15 V,because of the fewer side reactions.In addition,Nao.44Mn02 showed an exceptional ability to sustain overcharging up to 30％in a concentrated alkaline electrolyte(based关键词
钠离子电池/Na0.44MnO2/电化学性能/浓度/过充Key words
Sodium ion battery/Nao.44Mn02/Electrochemical performance/Concentration/Overcharging分类
化学化工引用本文复制引用
李慧,陈重学,曹余良,刘双宇,袁天赐,王博,盛鹏,徐丽,赵广耀,白会涛,陈新..NaOH浓度对Na0.44Mn02储钠性能的影响[J].物理化学学报,2021,37(3):73-79,7.基金项目
The project was supported by the Science and Technology Project of State Grid,China(SGRIDGKJ[2017]841),the National Key Basic Research Program of China(2016YFB0901500)and the National Natural Science Foundation of China(21875171,21673165).国家电网公司(SGRIDGKJf20171841)、国家重点基础研究发展计划(2016YFB0901500)和国家自然科学基金(21875171,21673165)资助项目 （SGRIDGKJ[2017]841）
