Li_(x)(Mg,Ni,Zn,Cu,Co)_(1-x)O高熵氧化物负极材料电化学储锂特性  

Electrochemical performance of chemical prelithiated Li_(x)(Mg,Ni,Zn,Cu,Co)_(1-x)O high-entropy oxide as anode material for lithium ion battery

作　　者：刘树港 蒙波 李政隆 杨亚雄 陈建[1] LIU Shugang;MENG Bo;LI Zhenglong;YANG Yaxiong;CHEN Jian(The Materials Science and Chemical Engineering of Xi'an Technological University,Xi'an 710021,Shaanxi,China;The Fourth Academy of CASC,Xi'an 710025,Shaanxi,China;Institute of Science and Technology for New Energy of Xi'an Technological University,Xi'an 710021,Shaanxi,China)

机构地区：[1]西安工业大学材料与化工学院,陕西西安710021 [2]中国航天科技集团有限公司第四研究院,陕西西安710025 [3]西安工业大学新能源科学与技术研究院,陕西西安710021

出　　处：《储能科学与技术》2023年第3期743-753,共11页Energy Storage Science and Technology

基　　金：国家自然科学基金青年项目(51901168);陕西省高校科协青年人才托举计划项目(20200428)。

摘　　要：高熵氧化物是一种新型单相固溶体材料,作为转换反应类型的锂离子电池负极材料近年来受到了广泛关注。本工作通过氧化物与LiH固相加热反应合成了预锂化的单相Li_(x)(Mg,Ni,Zn,Cu,Co)_(1-x)O(x=0,0.08,0.16,0.2)高熵氧化物负极材料,并研究了其电化学储锂特性。结果表明,低价态Li^(+)在晶格中引入以及电荷补偿作用使得高熵氧化物中形成Co^(3+)、Ni^(3+)和氧空位,高价态Co^(3+)和Ni^(3+)的存在提高了转换反应的电子转移数;氧空位的形成提升了高熵氧化物的导电能力,有利于提高转换反应动力学;同时,非活性Mg^(2+)充当缓冲基质保证了电化学过程中的结构稳定性。因此,预锂化的Li_(0.16)(Mg,Ni,Zn,Cu,Co)0.84O高熵氧化物负极材料在100 mA/g的电流密度下表现出679 mAh/g的高可逆比容量,63.7%的首次库仑效率,较小的电极极化(充放电平台电压差为-0.9 V),并且在1000 mA/g的高电流密度下,800次循环后可逆比容量仍保持在651 mAh/g,显示出优异的循环稳定性和倍率特性。High-entropy oxides,a new class of single-phase solid solution materials,have recently attracted significant attention as conversion-type anode material for lithium-ion batteries(LIBs).Prelithiated Li_(x)(Mg,Ni,Zn,Cu,Co)_(1-x)(x=0,0.08,0.16,0.2)high-entropy oxide anode materials are synthesized by a chemical reaction of LiH with metal oxides,and the electrochemical performance of the prepared high-entropy oxides are investigated in this study.Introduction of low-valence Li^(+)in the lattice and charge compensation effect facilitate the formation of Co^(3+),Ni^(3+)and oxygen vacancies.Existence of high-valence Co^(3+)and Ni^(3+)increases the electron transfer number of the conversion reaction.The oxygen vacancies promote the electron/ion transportation of the oxide electrode and improve the conversion reaction kinetics.Meanwhile,the inactive Mg^(2+)makes the high entropy oxides maintain the stable rock salt structure upon lithiation/delithiation,which ensures the structural stability during the electrochemical process.As a result,a high reversible specific capacity(679 mAh/g at 100 mA/g),an improved first Coulomb efficiency(63.7%),a decreased polarization(voltage discrepancy between charge and discharge plateaus of-0.9 V),a good cycling stability and high rate capability(reversible specific capacity of 651 mAh/g after 800 cycles at 1000 mA/g)are achieved for prelithiated Li_(0.16)(Mg,Ni,Zn,Cu,Co)0.84O high-entropy oxide anode material.

关 键 词：锂离子电池 负极材料 高熵氧化物 预锂化 

分 类 号：TM911.11[电气工程—电力电子与电力传动]