g-C3N4 Boosting the Interfacial Compatibility of Solid-State Lithium-Sulfur Battery

Abstract

The poor interfacial compatibility between solid electrolyte and lithium metal anode is one of the main obstacles to the development of solid lithium metal battery. Herein, the poly (1,3-dioxolane) (PDOL) polymer is combined with g-C3N4 powders to form a flexible and dense composite solid electrolyte film, which not only possesses high ionic conductivity of 3.7 × 10−4 S·cm−1, high ion migration number up to 0.86, and wide electrochemical stability window of 5.0 V, but also is helpful for inhibiting the growth of lithium dendrites to improve the interfacial stability of the lithium anode and close contact with cathode. The prepared S/g-C3N4-PDOL/Li battery exhibits good rate and cycle performances with a capacity of 550 mAh g−1 at 1 C, and 1150 mAh g−1 at 0.1 C with a capacity retention rate of 83% after 100 cycles. The dense Li3N layer generated by the reaction between g-C3N4 and Li gives g-C3N4/PDOL composite electrolyte a high inhibition ability of lithium dendrites. This composite solid electrolyte film with an interface modification function has good practical application prospects in lithium-sulfur batteries.