固相燃烧法制备去顶角八面体LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)正极材料及其电化学性能  

Synthesis and electrochemical properties of truncated octahedral LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)cathode material by solid-state combustion method

作　　者：王念 李萌 吉颖 向明武 郭昱娇 白红丽 刘晓芳 郭俊明 WANG Nian;LI Meng;JI Ying;XIANG Ming‑Wu;GUO Yu‑Jiao;BAI Hong‑Li;LIU Xiao‑Fang;GUO Jun‑Ming(Key Laboratory of Green-Chemistry Materials in University of Yunnan Province,School of Chemistry and Environment,Yunnan Minzu University,Kunming 650500,China;Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]云南民族大学化学与环境学院,云南省高校绿色化学材料重点实验室,昆明650500 [2]昆明理工大学环境科学与工程学院,昆明650093

出　　处：《无机化学学报》2023年第6期1042-1052,共11页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.51972282,U1602273)资助。

摘　　要：通过固相燃烧法快速合成了包含{111}、{100}和{110}晶面的单晶去顶角八面体形貌LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)正极材料。结果表明,Zn-Al共掺促进了尖晶石型LiMn_(2)O_(4)材料的晶体发育和晶面择优生长,形成了单晶去顶角八面体形貌晶粒,有效抑制了Jahn-Teller效应,减缓了Mn溶解,增强了其晶体结构稳定性,显著提升了合成材料的电化学性能。Li Zn_(0.08)Al_(0.01)Mn_(1.91)O_(4)在5C和10C下的首次放电比容量分别为92.6和76.5 mAh·g^(-1),经过2000次循环后的容量保持率分别为70.4%和74.8%。即使在15C高倍率下,仍有64.2 m Ah·g^(-1)的首次放电比容量,循环800次后容量保持率达到82.2%。与LiZn_(0.08)Mn_(1.92)O_(4)相比,LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)正极材料具有较大的Li+扩散系数(1.02×10^(-1)1cm^(2)·s^(-1))和较小的表观活化能(25.60 kJ·mol^(-1)),表明Zn-Al共掺和单晶形貌调控策略能够降低Li^(+)在脱/嵌过程的能垒和增大Li^(+)在电极材料中的扩散速率。A single-crystal truncated octahedral morphology LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)cathode material with{111},{110},and{100}crystal surfaces was synthesized by a solid-state combustion method.The results show that Zn-Al co-doped promotes the crystal development and the selective growth of crystal surfaces of spinel LiMn_(2)O_(4)materials,while forming single-crystal truncated octahedral grain.The Zn-Al co-doped sample effectively inhibits the JahnTeller effect and reduces Mn dissolution,thus enhancing the crystal structure stability and significantly improving the electrochemical performance.The initial discharge specific capacity of LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)were 92.6 and 76.5 mAh·g^(-1)at 5C and 10C,the corresponding capacity retention remained 70.4%and 74.8%after 2000 cycles,respectively.Even at a high current density of 15C,the initial discharge capacity was still 64.2 mAh·g^(-1),and the capacity retention can reach 82.2%after 800th cycles.Compared with LiZn_(0.08)Mn_(1.92)O_(4),the LiZn_(0.08)Al_(0.01)Mn_(1.91)O_(4)cathode material had a larger Li+diffusion coefficient(1.02×10^(-1)1 cm^(2)·s^(-1))and smaller apparent activation energy(25.60kJ mol^(-1)).The results show that the Zn-Al co-doped and monocrystalline morphology control strategy can reduce the energy barrier of Li^(+)during the de-intercalation process and increase the diffusion rate in electrode materials.

关 键 词：LiMn_(2)O_(4) Zn-Al共掺 正极材料 JAHN-TELLER效应 Mn溶解 去顶角八面体 固相燃烧法 

分 类 号：TM912[电气工程—电力电子与电力传动]