GaN nanorods/N–doped carbon derived from Ga–MIL–68 as a separator coating for suppressing the shuttle effect in lithium–sulfur batteries

Abstract

Lithium–sulfur batteries (LSBs) offer high theoretical energy density, yet their practical deployment is constrained by lithium polysulfide (LiPS) shuttling, sluggish sulfur redox kinetics, and unstable lithium deposition. This work addresses whether a single separator coating can simultaneously regulate polysulfide chemistry and the lithium-metal interface. A MOF-derived GaN nanorod/N-doped carbon (GaN-NC) composite is synthesized from Ga-MIL-68 and melamine and applied as a multifunctional coating on a PP separator. The novelty of this design lies in integrating polar and catalytically active GaN with a conductive N-doped carbon network in a rod-like MOF-derived architecture, thereby coupling LiPS adsorption/conversion, charge transport, and Li + -flux regulation within one functional layer. Cells using GaN-NC//PP deliver a capacity of 770.5 mAh g −1 at a current density of 3 C and retain 507.3 mAh g −1 after 500 cycles at 1 C, corresponding to a capacity decay rate of 0.102% per cycle. At a sulfur loading of 8.28 mg cm −2 , an areal capacity of 3.98 mAh cm −2 is maintained after 50 cycles. These results demonstrate an integrated separator strategy for concurrently improving sulfur redox kinetics and lithium-anode stability in LSBs.