| 固相燃烧法制备去顶角八面体LiZn0.08Al0.01Mn1.91O4正极材料及其电化学性能 |
| Synthesis and electrochemical properties of truncated octahedral LiZn0.08Al0.01Mn1.91O4 cathode material by solid-state combustion method |
| 作者 | 单位 | E-mail | | 王念 | 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 | | | 李萌 | 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 | | | 吉颖 | 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 | | | 向明武 | 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 | | | 郭昱娇 | 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
昆明理工大学环境科学与工程学院, 昆明 650093 | guoyujiao1988@163.com | | 白红丽 | 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 | | | 刘晓芳 | 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 | | | 郭俊明 | 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 | guojunming@tsinghua.org.cn |
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| 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LiZn0.08Al0.01Mn1.91O4正极材料。结果表明,Zn-Al共掺促进了尖晶石型LiMn2O4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。LiZn0.08Al0.01Mn1.91O4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2 000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 mAh·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LiZn0.08Mn1.92O4相比,LiZn0.08Al0.01Mn1.91O4正极材料具有较大的Li+扩散系数(1.02×10-11 cm2·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。 |
| 关键词: LiMn2O4 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 |
| 基金项目: 国家自然科学基金(No.51972282，U1602273)资助。 |
| Abstract: A single-crystal truncated octahedral morphology LiZn0.08Al0.01Mn1.91O4 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 LiMn2O4 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 LiZn0.08Al0.01Mn1.91O4 were 92.6 and 76.5 mAh·g-1 at 5C and 10C, the corresponding capacity retention remained 70.4% and 74.8% after 2 000 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 LiZn0.08Mn1.92O4, the LiZn0.08Al0.01Mn1.91O4 cathode material had a larger Li+ diffusion coefficient (1.02×10-11 cm2·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. |
| Keywords: LiMn2O4 Zn-Al co-doping cathode material Jahn-Teller effect Mn dissolution truncated octahedron solid-state combustion method |
| 投稿时间：2022-12-25 修订日期：2023-05-09 |
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| 王念,李萌,吉颖,向明武,郭昱娇,白红丽,刘晓芳,郭俊明.固相燃烧法制备去顶角八面体LiZn0.08Al0.01Mn1.91O4正极材料及其电化学性能[J].无机化学学报,2023,39(6):1042-1052. |
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