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

A strategy for the constructing of the cathode–electrolyte interface (CEI) film assisted by AlF3 as a cathode host for lithium–selenium batteries is proposed and realized. A simple one-step method for the conversion of porous carbon containing Al particles (PC/Al) to layered AlF3 (PC/AlF3) 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 AlF3 in the interlayer and intracavity of PC shows strong chemical adsorption toward polyselenides. Moreover, AlF3 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/AlF3–Se cathode presents a satisfying discharge capacity of 580 mAh g–1 at 5 C. Even at 10 C, the PC/AlF3–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.