In Situ Generation of AlF₃ in Nanoporous Carbon to Enable Cathode–Electrolyte Interface Construction for Stable Li–Se Batteries

Abstract

A strategy for the constructing of the cathode− electrolyte interface (CEI) film assisted by AlF 3 as a cathode host for lithium−selenium batteries is proposed and realized. A simple onestep method for the conversion of porous carbon containing Al particles (PC/Al) to layered AlF 3 (PC/AlF 3 ) was employed. The stable PC substrate with multidirectional channels alleviates the volume expansion and improves the electron conductivity during cycling. At the same time, the uniform dispersion of AlF 3 in the interlayer and intracavity of PC shows strong chemical adsorption toward polyselenides. Moreover, AlF 3 boosts the construction of the CEI film, which further serves as a blocked layer grown on the cathode interface to prevent subsequent side reactions. Hence, the PC/AlF 3 −Se cathode presents a satisfying discharge capacity of 580 mAh g −1 at 5 C. Even at 10 C, the PC/AlF 3 −Se cathode achieved long cycling stability with a capacity decay rate of 0.028% for 1000 long cycles. This strategy provides an insight into facilitating the formation of CEI film toward highly stable Li−Se batteries.