Cooperative Effect of Multiple Active Sites and Hierarchical Chemical Bonds in Metal-Organic Compounds for Improving Cathode Performance
Cooperative Effect of Multiple Active Sites and Hierarchical Chemical Bonds in Metal-Organic Compounds for Improving Cathode Performance
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金属有机化合物中多个活性位点和多级化学键对提高正极性能的协同作用
DOI：
10.1021/acsenergylett.9b02630
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发表时间：
2020
影响因子：
22
通讯作者：
Liu Jianjun
中科院分区：
文献类型：
--
作者：
Zhao Xiaolin;Cui Mengnan;Ma Chao;Qiu Wujie;Wang Youwei;Song Erhong;Wang Kaixue;Liu Jianjun
具有低溶解度和更可行的生态有效生产的金属-有机阴极化合物仍然遭受相对低的电压和有限的放电容量，因为它们的氧化还原反应仅依赖于活性有机官能团或金属簇。在此，通过第一性原理计算，证明金属有机化合物Cu 2（p-O2 NC 6 H4 CO2）4（EtO）2具有243 mA h g-1的高容量和相对于Li+/Li的3.66、3.15、2.25和2.08 V的高压平台。电子结构分析表明，Cu 2+参与Cux+（1 <x< 2）和Oy-（1 <y< 2）参与O2-在金属配体部分和N5+参与Nx+（4 <x< 5）和O2-参与Oz-（1 <z< 2）在− NO2基团，通过操作基于多个活性位点和分级化学键的协同阳离子-阴离子氧化还原反应实现高电压和容量。此外，Cu 2（p-O2 NC 6 H4 CO2）4（EtO）2还被预测具有良好的电化学可逆性，因为阳离子转化反应被更高电压的阴离子反应和[MO 5]n-的分级化学键抑制。本研究为设计高性能的金属有机阴极化合物提供了一种策略。
Metal–organic cathode compounds with low solubility and more viable eco-efficient production still suffer from relatively low voltage and limited discharge capacity because their redox reactions solely rely on active organic functional groups or metal clusters. Here, a metal–organic compound Cu2(p-O2NC6H4CO2)4(EtO)2was demonstrated to have high capacity of 243 mA h g–1and high-voltage plateaus of 3.66, 3.15, 2.25, and 2.08 V vs Li+/Li through first-principles calculations. Electronic structure analysis reveals Cu2+↔ Cux+(1 <x< 2) and Oy–(1 <y< 2) ↔ O2–in a metal–ligand moiety and N5+↔ Nx+(4 <x< 5) and O2–↔ Oz–(1 <z< 2) in −NO2groups, achieving high voltage and capacity by operating cooperative cationic–anionic redox reactions based on multiple active sites and hierarchical chemical bonds. Furthermore, the Cu2(p-O2NC6H4CO2)4(EtO)2is also predicted to have good electrochemical reversibility because the cationic conversion reaction is inhibited by a higher-voltage anionic reaction and hierarchical chemical bonds of [MO5]n−. The present study provides a strategy to design metal–organic cathode compounds with high performance.