Recent Progress of Porous Polymers for Lithium Metal Anodes Protection

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.

Automated summary

Lithium metal batteries face challenges such as dendrite growth, unstable interfaces, and low Coulombic efficiency. Porous polymers, with their high surface area and controllable structure, are emerging as a promising solution for these issues. By constructing artificial solid electrolyte interphase layers, coating separators with functional layers, and designing metal anode structures, porous polymers can enhance the performance of lithium metal batteries.