| 正极材料LiAl0.08Mn1.92O4单晶颗粒形貌演变及电化学性能 |
| Morphological evolution and electrochemical properties of cathode material LiAl0.08Mn1.92O4 single crystal particles |
| 作者 | 单位 | E-mail | | 朱琴 | 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 | | | 马姣 | 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 | | | 钱志慧 | 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 | | | 罗宇旭 | 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 | | 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 | | | 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 | | | 宁平 | 昆明理工大学环境科学与工程学院, 昆明 650093 | | | 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: 联合元素掺杂和形貌调控策略，采用固相燃烧法和不同焙烧温度处理合成LiAl0.08Mn1.92O4正极材料。实验结果表明，Al掺杂和焙烧温度的变化未改变LiMn2O4的相结构，随着温度的升高，结晶性增强，颗粒尺寸增大，其中焙烧温度650 ℃是形成截断八面体单晶颗粒形貌的关键温度，750 ℃是颗粒突然变大的突变温度。650 ℃优化焙烧温度下焙烧的LiAl0.08Mn1.92O4形成了较完整的包含(111)、(110)和(100)晶面的截断八面体单晶颗粒形貌，表现出优良的电化学和动力学性能。在1C下其首次放电比容量为 112.0 mAh·g-1，循环 500次后容量保持率为 72.9%，在 5C和 10C倍率下，其首次放电比容量可达到 107.1和 100.4 mAh·g-1，经 2 000 次长循环后，容量保持率为 52.2% 和 53.5%。并且具有最小氧化还原峰电位差(ΔEp2，循环前后分别为 0.109 和0.114 V)、最小电荷转移电阻(Rct，循环前后分别 106.49和 125.49 Ω)及较大的锂离子扩散系数(DLi+ =1.72×10-16 cm2·s-1)，表现出较好的电化学可逆性和较快的锂离子扩散速率。Al掺杂和单晶截断八面体颗粒形貌既有效抑制了 LiMn2O4的 Jahn-Teller 畸变，又降低了Mn溶解，提高了材料的倍率性能和长循环寿命。 |
| 关键词: 尖晶石LiMn2O4 Al掺杂 固相燃烧法 焙烧温度 形貌调控 截断八面体 |
| 基金项目: 国家自然科学基金(No.51972282)资助。 |
| Abstract: Combined with the element doping and morphology controlling strategies, the LiAl0.08Mn1.92O4 cathode material was synthesized by solid-state combustion method and dealt with at different calcination temperatures (600, 650, 700, and 750 ℃). The experimental results showed that the phase structure of LiMn2O4 was not changed by Al doping and the change of calcination temperature. With the increase in temperature, the crystallinity of the sample increased and the particle size enlarged. The calcination temperature of 650 ℃ was the key temperature for the formation of truncated octahedral single crystal particle morphology, and 750 ℃ was the abrupt temperature of the particles that suddenly became larger. The LiAl0.08Mn1.92O4 material with an optimized calcination temperature of 650 ℃ formed a relatively complete truncated octahedral single crystal morphology particle containing (111), (110), and (100) crystal planes, and showed excellent electrochemical and kinetic performance. The initial discharge capacity was 112.0 mAh·g-1 at 1C, and the capacity retention rate was 72.9% after 500 cycles. The initial discharge capacities were 107.1 and 100.4 mAh·g-1 at 5C and 10C, and the capacity retention rates were 52.2% and 53.5% after 2 000 cycles, respectively. It had the minimum redox peak potential difference (ΔEp2=0.109 and 0.114 V before and after cycling respectively), the minimum charge transfer resistance (Rct=106.49 and 125.49 Ω before and after cycling respectively), and the large lithium-ion diffusion coefficient (DLi+ =1.72×10-16 cm2·s-1). The Al doping and single crystal truncated octahedral particle morphology not only effectively inhibited the Jahn Teller effect of LiMn2O4 but also relieved the dissolution of Mn, and improved the rate performance and long cycle life of the materials. |
| Keywords: spinel LiMn2O4 Al-doping solid-state combustion method calcination temperature morphology control truncated octahedrona |
| 投稿时间：2024-04-26 修订日期：2024-06-06 |
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| 朱琴,马姣,钱志慧,罗宇旭,郭昱娇,向明武,刘晓芳,宁平,郭俊明.正极材料LiAl0.08Mn1.92O4单晶颗粒形貌演变及电化学性能[J].无机化学学报,2024,40(8):1549-1562. |
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