摘要/Abstract
锂金属负极具有极高的理论比容量和最低的还原电位, 因此锂金属电池被认为是最具潜力的高比能储能器件之一. 然而, 充放电过程中不受控制的枝晶生长、不稳定的界面反应与巨大的体积变化导致锂金属负极库伦效率低与循环稳定性差, 同时枝晶刺穿隔膜也会带来安全隐患, 这些问题极大地制约着锂金属电池的实际应用. 多孔聚合物由于比表面积大、密度低、孔结构与微化学环境易裁剪等特点, 能够有效促进锂离子传输和均匀沉积, 已逐渐成为“无枝晶”锂金属电池研究领域的“新宠”. 然而, 相关的研究依然处于起步阶段, 本综述从人工固体电解质界面膜、隔膜修饰层与锂负极结构设计三个方面对多孔聚合物在锂金属电池负极保护中的研究进行了介绍与评述.
关键词: 锂金属电池, 锂枝晶, 负极保护, 多孔聚合物, 孔结构
Lithium metal batteries (LMBs) are regarded as one of the most promising candidates for next-generation high-energy-density devices, due to the high theoretical specific capacity and low electrochemical potential of lithium metal anode. However, the uncontrollable growth of Li dendrite, unstable Li/electrolyte interface and infinite volume fluctuation during charge/discharge process give rise to low Coulombic efficiency, poor cycle stability and even serious safety hazard from internal short-circuit via dendrite penetration through separators. These multifaceted problems severely hinder the practical applications of LMBs. Featured by high specific surface area, low density, controllable pore structure, and flexible molecular design of pore surface/skeleton functionality, porous polymers have received growing attention in electrochemical energy storage, especially for lithium anode protection. The nanopores and tailored functionalities could allow for facilitated Li ion transport, while inhibiting anions and regulating the grain size and distribution of LiF. The large pores are conducive to accommodating lithium deposition and lowing of local current density. Consequently, porous polymers have become the “new favorite” in the field of “dendrite-free” LMBs recently, which show great potential for stabilizing Li metal anode. However, explorations in this field still remain in their infancy, and the objective of this review is to briefly summarize the research progress of porous polymers, especially crystalline covalent organic frameworks for lithium metal anodes protection, by means of constructing the artificial solid electrolyte interphase layer, coating separator with functional layers and designing metal anode structure.
Key words: lithium metal battery, Li dendrite, anode protection, porous polymer, pore structure
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