高温型锰酸锂正极材料的晶体形貌控制和电化学性能  

Morphology-control preparation and electrochemical performance of Mn-spinel cathode materials

作　　者：赛喜雅勒图[1] 胡华胜[1] 夏永高[1] 肖锋[1] 刘兆平[1] 

机构地区：[1]中国科学院宁波材料技术与工程研究所,宁波315201

出　　处：《科学通报》2013年第32期3350-3356,共7页Chinese Science Bulletin

基　　金：宁波市科技创新团队项目(2012B82001);浙江省自然科学基金(LY13B030007)资助

摘　　要：尖晶石锰酸锂动力电池循环寿命较短和储藏性能差的主要原因之一是锰酸锂的锰易溶解于电解液中,特别在高温下(60℃)锰的溶解尤为严重.目前,锰酸锂的高温容量衰减机理虽已得到广泛的研究,但主要集中在脱嵌锂过程中的结构变化与容量之间的关系上.事实上,锰酸锂表面结构(晶面)及其界面反应很大程度上影响Mn的溶解.本文在控制锰酸锂氧缺陷的基础上,通过结合设计类球形锰酸锂单晶颗粒,可以减小其(111)晶面的面积,从而减少锰的溶解,进而提高锰酸锂材料的晶体结构稳定性和高温循环性能.结果表明,由这种类球形锰酸锂正极材料制作成的18650型电池具有优异的循环性能,在常温下1 C倍率充放电循环2500次后,电池容量保持率维持在80%左右;即使在60℃高温下,400次循环后,容量保持率仍达80%.The disadvantage of the LiMn204 batteries is a capacity fade during charge-discharge cycling or high temperature storage. It is well known that this deterioration is mainly caused by Mn dissolution from spinel, especially at elevated temperature （60℃）. Extensively studies have been made to explain its degraded cycling performance, but these studies mainly focused on investigating the structural change during lithium intercalation/de-intercalation process. In fact, the recent researches have shown that the surface structure and interface reaction of Mn-spinel greatly affect the Mn dissolution of spinel. In this study, we have successfully synthesized oxygen stoichiometric Mn-spinel cathode with spherical-like morphology. It has a much smaller （111） plane area compared with the single crystal octahedral or polyhedral Mn-spinel products. The decrease of the plane area could reduce the Mn dissolution during cycling process, which made it have better cycling performance than the commercial products. The electrochemical test results showed that 18650 cylinder batteries using this spherical-like Mn-spinel retention of 80% after 2500 cycles at room temperature. Even after 400 cycles. cathode material has an excellent cycle performance with the capacity at elevated temperature of 60℃, the capacity retention still reached 80%

关 键 词：尖晶石锰酸锂 正极材料 形貌 锰溶解 

分 类 号：TM912[电气工程—电力电子与电力传动]