Boosting Polysulfide Redox Kinetics by Temperature-Induced Metal-Insulator Transition Effect of Tungsten-Doped Vanadium Dioxide for High-Temperature Lithium-Sulfur Batteries.

The practical application of Li-S batteries is still severely restricted by poor cyclic performance caused by the intrinsic polysulfides shuttle effect, which is even more severe under the high-temperature condition owing to the inevitable increase of polysulfides' solubility and diffusion rate. Herein, tungsten-doped vanadium dioxide (W-VO) micro-flowers are employed with first-order metal-insulator phase transition (MIT) property as a robust and multifunctional modification layer to hamper the shuttle effect and simultaneously improve the thermotolerance of the common separator. Tungsten doping significantly reduces the transition temperature from 68 to 35 °C of vanadium dioxide, which renders the W-VO easier to turn from the insulating monoclinic phase into the metallic rutile phase.

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 VO@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 VO and rGO induces self-driven charge redistribution, resulting in accelerated charge transport rates, enhanced LiPS chemisorption, reduced energy barriers for LiS nucleation/decomposition, and improved Li-ion diffusion behavior.