Graphitic carbon nitride stabilized the lithium anode/sulfide electrolyte interface for all-solid-state lithium-sulfur battery

Sulfide solid-state electrolytes (SSEs) are expected to fundamentally avoid the polysulfides shuttle and Li dendrites growth in the traditional liquid electrolyte lithium-sulfur (Li-S) batteries owing to its ultrahigh ionic conductivity, the high mechanical strength and favorable interfacial compatibility with sulfide-based cathodes. However, the sulfide SSEs are thermodynamically unstable to Li metal, and the parasitic reactions between the Li anode and sulfide SSEs results in intolerable interface deterioration. Herein, a graphitic carbon nitride (GCN, g-C3N4)-dominated artificial interlayer was introduced to enhance the interfacial stability between Li metal and sulfide SSEs. The introduction of electrochemically inert GCN is revealed to effectively alleviate the formation of heterogenous resistance layers for long-term. Furthermore, the abundant nitrogen species within GCN layer homogenize the distribution of Li ions flux, which effectively smooths Li deposition and suppresses dendrites growth. Herein, the symmetric cells with the Li-GCN show a stable plating/stripping cycling for over 1100 h at 0.2 mA cm−2 and a capacity of 0.2 mAh cm−2. The all-solid-state Li-SPAN battery with g-C3N4 interphase exhibits a highly reversible capacity of 579 mAh g−1 and a capacity retention of 88 % at 0.2C after 150 cycles, as well as achieves an excellent rate performance.