离子嵌入电化学反应机理的理解及性能预测:从晶体场理论到配位场理论  

Understanding and performance prediction of ions-intercalation electrochemistry:From crystal field theory to ligand field theory

作　　者：王达 周航 焦遥 王佳民 施维 蒲博伟 李铭清 宁芳华 任元 喻嘉 李亚捷 李彪 施思齐[1,2,5] WANG Da;ZHOU Hang;JIAO Yao;WANG Jiamin;SHI Wei;PU Bowei;LI Mingqing;NING Fanghua;REN Yuan;YU Jia;LI Yajie;LI Biao;SHI Siqi(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;Materials Genome Institute,Shanghai University,Shanghai 200444,China;Institute for Sustainable Energy/College of Sciences,Shanghai University,Shanghai 200444,China;Collège deFrance,Paris UMR 8260,France;Zhejiang Laboratory,Hangzhou 311100,Zhejiang,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444 [2]上海大学材料基因组工程研究院,上海200444 [3]上海大学可持续能源研究院,上海200444 [4]法兰西学院,法国巴黎UMR 8260 [5]之江实验室,浙江杭州311100

出　　处：《储能科学与技术》2022年第2期409-433,共25页Energy Storage Science and Technology

基　　金：国家重点研发计划项目(2021YFB3802104);国家自然科学基金优秀青年科学基金项目(51622207);国家自然科学基金面上项目(11874254);国家自然科学基金青年项目(51802187);国家自然科学基NSAF联合基金重点项目(U2030206);上海先进陶瓷结构设计与精密制造专业技术服务平台(20DZ2294000);之江实验室科研攻关项目(2021PE0AC02)。

摘　　要：配位场理论融合了晶体场的静电作用和分子轨道的共价作用于1952年首次被提出,是解析热力学、地质矿物学和电化学系统中的结构畸变、热力学性质和磁性等物理/化学问题的基础。其中对于近年来快速发展的单价/多价金属离子电池领域,其电极材料通常是含有d电子的过渡金属化合物,目前仍普遍存在对具有不同配位场过渡金属电极材料中离子脱嵌电压、比容量以及相结构稳定等微观结构/电荷转移性能调控机理认识的不足。本文从配位场理论方法出发并结合可直接计算电子分布及占据特性的第一性原理计算方法,对离子脱嵌电化学过程中决定电压的费米能级计算模型、衡量相结构稳定性的晶体场稳定化能计算公式、调控阴离子氧化还原活性的理论模型等进行了严格的推导。在此基础上,提出针对刚性带体系的电压调控和含不同周期过渡金属材料相结构稳定性预测等一系列电极能量密度/相稳定性改进策略,并成功设计出无过渡金属Li(Na)BCF_(2)/Li(Na)B_(2)C_(2)F_(2)正极及嵌入式反应无锂MX_(2)正极两种新型电极材料。本工作拓展了配位场理论在离子嵌入电化学中的应用,为从电子的能带调控角度设计高能量密度嵌入式电极材料提供了新思路。The ligand field theory,which combines the electrostatic interaction of crystal fields and the covalent interaction of molecular orbitals,was first proposed in 1952.It has become the basis for studying many physical/chemical problems in thermodynamic,geological,mineralogical and electrochemical systems,such as structural distortion,thermodynamic properties and magnetism.Among them,for the rapidly developing mono-/poly-valent metalion batteries field,the electrode materials used are primarily transition metal(TM)compounds containing d electrons.However,the understanding of the regulation of microstructural/electronic performances with different coordination fields,such as ion-(de)intercalating voltage,specific capacity and phase structure stability is still incompletely understood.In this paper,by combining the ligand field theory method and first-principles calculations(FP/DFT)that can directly obtain the system electronic distribution/occupancy,the Fermi level calculation model that determines the ions-intercalation voltage,the crystal field stabilization energy formula that measures the phase stability,and the theoretical model for regulating anionic redox activity are rigorously deduced.On this basis,we propose a series of electrodes energy-density/phase-stability improvement strategies,viz.,voltage regulation of rigid band system and phase stabilization prediction of TM-containing electrodes with different TM period.Finally,two new cathodes,the TM-free Li(Na)BCF_(2)/Li(Na)B_(2)C_(2)F_(2) and the lithium-free intercalation-type MX_(2) are successfully designed.This work expands the application of ligand field theory in ionsintercalation electrochemistry and opens up a new avenue for designing high-energy-density ions-intercalation electrode materials through electronic band structure regulation engineering.

关 键 词：晶体场理论 配位场理论 阴离子氧化还原活性 费米能级 电子结构调控 

分 类 号：TM911[电气工程—电力电子与电力传动]