用于Li-CO_(2)电池的过渡金属及其合金催化剂研究进展

Research progress on transition metals and their alloy catalysts for Li-CO_(2)batteries

【目的】提升锂-二氧化碳(Li-CO_(2))电池的反应可逆性和动力学特性,概括Li-CO_(2)电池的简史、结构、工作原理以及关键科学问题,综述用于Li-CO_(2)电池的过渡金属及其合金催化剂的成分、形貌、微观结构等特性及其对Li-CO_(2)电池性能的影响,分析过渡金属及其合金催化剂在催化过程中的作用机制和演化行为。【研究现状】过渡金属对反应物吸附与活化、放电产物沉积及分解具有促进作用。基于过渡金属元素构筑的单金属和双金属正极催化剂,在Li-CO_(2)电池中的催化活性、作用机制及其自身在催化过程中的演化各不相同。金属间化合物具有显著区别于固溶合金、单分散双金属、单一金属的化学微环境,因此在促进反应物种吸附与活化、产物分解等方面表现出独特优势。【结论与展望】过渡金属及其合金催化剂的未来研究方向有:调控催化剂宏观形貌和表面微结构;监测催化过程中催化剂结构与成分演化、放电产物沉积与分解行为;建立适用于Li-CO_(2)电池的催化剂关键“描述符”;开发低成本催化剂量产工艺。

Significance To enhance the reversibility and kinetics of Li-CO_(2) batteries,this paper summarizes the history,structure,working principle,and key scientific challenges of Li-CO_(2) batteries.It reviews the composition,morphology,microstructure,and other characteristics of transition metal and alloy catalysts used in Li-CO_(2) batteries and analyzes their impact on battery performance.Furthermore,the catalytic mechanisms and evolutionary behaviors of these catalysts during the reaction process are examined.Progress Transition metals exhibit incomplete d orbitals,abundant and adjustable valence states,and ease of processing,allowing them for broad applications in Li-CO_(2) batteries.3 d transition metals such as Ni,Co,Fe,Cu,and Zn,4 d transition metals such as Ru,Pd,and Ag,and 5d transition metals such as Ir and Au,all promote reactant adsorption and activation,as well as the deposition and decomposition of discharge products.Single-metal and bimetallic cathode catalysts constructed based on these elements show different catalytic activities,mechanisms,and evolutionary behaviors during catalytic process in Li-CO_(2) batteries.Ni and Co undergo no redox reactions during catalysis.Cu tends to oxidize during charging and cannot effectively catalyze the co-decomposition of Li_(2)CO_(3) and elemental C,while CuO formed through oxidation during charging and discharging can significantly enhance the reversibility of battery reactions.Fe undergoes redox reactions between Fe—O—C and Fe in Li-CO_(2) batteries.Zn can catalyze CO_(2) reduction to generate Li_(2)CO_(3) and CO products in proton-based Li-CO_(2) batteries.The electron configuration of Pd facilitates the weakening of Li-O bonds and the activation of Li2CO3,exhibiting smaller charge-discharge polarization compared to other precious metals such as Ru,Ag,Ir,and Au.Intermetallic compounds possess unique chemical microenvironments significantly different from those of solid solution alloys,monodisperse bimetals,and single metals in atomic configurations,electronic structures,and chemical bonding,thus demonstrating distinctive advantages in promoting reactant adsorption and activation and product decomposition.Conclusions and Prospects The study proposes several research directions for transition metals and alloy catalysts.Regulating the macroscopic morphology and surface microstructure of catalysts,as an important means to improve the density and intrinsic activity of active sites,modulate the adsorption and activation of species during reactions,and change the battery reaction pathway.Monitoring the evolution of catalyst structure and composition during the catalytic process,as well as the deposition and decomposition behaviors of discharge products,to summarize the internal relationships between catalyst composition,structure,and performance.This can provide theoretical support for catalyst design,failure analysis,and re-optimization.Establishing key“descriptors”of catalysts suitable for Li-CO_(2) batteries to reduce trial-and-error processes and promote the development of high-performance catalysts.Developing cost-effective catalyst mass production techniques to select low-cost catalysts that can be applied in practical engineering,thereby guiding scientific research efforts and facilitating the practical development of Li-CO_(2) batteries.