Manipulating Sulfur Conversion Kinetics through Interfacial Built-In Electric Field Enhanced Bidirectional Mott–Schottky Electrocatalysts in Lithium–Sulfur Batteries

Efficient electrocatalysts and catalytic mechanisms remain a pressing need in Li–S electrochemistry to address lithium polysulfide (LiPS) shuttling and enhance conversion kinetics. This study presents the development of multifunctional VO2@rGO heterostructures, incorporating interfacial built-in electric field (BIEF) enhancement, as a Mott–Schottky electrocatalyst for Li–S batteries. Electrochemical experiments and theoretical analysis demonstrate that the interfacial BIEF between VO2 and rGO induces self-driven charge redistribution, resulting in accelerated charge transport rates, enhanced LiPS chemisorption, reduced energy barriers for Li2S nucleation/decomposition, and improved Li-ion diffusion behavior. The Mott–Schottky electrocatalyst, combining the strengths of VO2’s anchoring ability, rGO’s metallic conductivity, and BIEF’s optimized charge transport, exhibits an outstanding “trapping–conversion” effect. The modified Li–S battery with a VO2@rGO-modified separator achieves a highly reversible capacity of 558.0 mAh g–1 at 2 C over 600 cycles, with an average decay rate of 0.048% per cycle. This research offers valuable insights into the design of Mott–Schottky electrocatalysts and their catalytic mechanisms, advancing high-efficiency Li–S batteries and other multielectron energy storage and conversion devices.