Li + mobility powered by a crystal compound for fast Li-S chemistry.

Placing blocking layers between electrodes has shown paramount prospects in suppressing the shuttle effect of Li-S batteries, but the associated ionic transport would be a concurrent obstacle. Herein, we present a Li-based crystal composited with carbon (LiPN 2 @C) by a one-step annealing of Li + absorbed melamine polyphosphate, which simultaneously achieves alleviated polysulfide-shuttling and facilitated Li + transport. As a homologous crystal, LiPN 2 with abundant lithiophilic sites makes Li + transport more efficient and sustainable. With a LiPN 2 @C-modified separator, the Li 2 S cathode exhibits a much-lower activation potential of 2.4 V and a high-rate capacity of 519 mA h g -1 at 2C. Impressively, the battery delivers a capacity of 726 mA h g -1 at 0.5C with a low decay rate of 0.25% per cycle during 100 continuous cycles.