Microemulsion synthesis of ZnMn2O4/Mn3O4 sub-microrods for Li-ion batteries and their conversion reaction mechanism  

微乳液法制备锂离子电池用ZnMn2O4/Mn3O4亚微米棒及其转化反应机理

作　　者：Ting-ting FENG Jian YANG Si-yi DAI Jun-chao WANG Meng-qiang WU 冯婷婷;杨俭;代思忆;王俊超;吴孟强(电子科技大学材料与能源学院,成都611731)

机构地区：[1]School of Materials and Energy,University of Electronic Science and Technology of China,Chengdu 611731,China

出　　处：《Transactions of Nonferrous Metals Society of China》2021年第1期265-276,共12页中国有色金属学报（英文版）

基　　金：Ting-ting FENG acknowledges the financial support from Professor Paul V.BRAUN at Department of Materials Science and Engineering,University of Illinois at Urbana-Champaign,the support from Chinese Scholarship Council during her visit to University of Illinois at Urbana-Champaign,partial financial supports from Department of Science and Technology of Sichuan Province,China(2019YFH0002,2019YFG0222 and 2019YFG0526).The research was partly carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities,University of Illinois at Urbana-Champaign.

摘　　要：The hierarchical ZnMn2O4/Mn3O4 composite sub-microrods were synthesized via a water-in-oil microemulsion method followed by calcination.The ZnMn2O4/Mn3O4 electrode displays an intriguing capacity increasing from 440 to 910 mA·h/g at 500 mA/g during 550 consecutive discharge/charge cycles,and delivers an ultrahigh capacity of 1276 mA·h/g at 100 mA/g,which is much greater than the theoretical capacity of either ZnMn2O4 or Mn3O4 electrode.To investigate the underlying mechanism of this phenomenon,cyclic voltammetry and differential capacity analysis were applied,both of which reveal the emergence and the growth of new reversible redox reactions upon charge/discharge cycling.The new reversible conversions are probably the results of an activation process of the electrode material during the cycling process,leading to the climbing charge storage.However,the capacity exceeding the theoretical value indicates that there are still other factors contributing to the increasing capacity.采用油包水微乳液法再经煅烧制备分级ZnMn2O4/Mn3O4复合亚微米棒。ZnMn2O4/Mn3O4电极在550次连续放电/充电循环中,在500 mA/g充放电电流条件下,其比容量从440 mA·h/g增加到910 mA·h/g,并在100 mA/g下提供1276 mA·h/g的超高比容量,远高于ZnMn2O4或Mn3O4的理论比容量。采用循环伏安法和微分容量分析法研究这种现象的潜在机制,两者均揭示在充放电循环过程中新的可逆氧化还原反应的产生和增强。这种新的可逆转化反应可能是由于电极材料在循环过程中的活化过程引起的,从而解释电极材料容量在循环过程中不断上升的现象;而容量超过理论值表明还有其他因素对容量的增长起作用。

关 键 词：ZnMn2O4/Mn3O4 sub-microrods MICROEMULSION conversion reaction mechanism cyclic voltammetry differential capacity analysis 

分 类 号：TM912[电气工程—电力电子与电力传动] TB34[一般工业技术—材料科学与工程]