In Situ Thermally‐Driven Radial Heterophase Evolution of δ‐Bi ₂ O ₃ Modulates the <i>p</i> ‐Block Bi <i>6p</i> Orbitals and <i>p</i> ‐Band Center for Enhancing Sulfur Redox Reactions

Abstract

Abstract The commercialization of lithium–sulfur batteries is hindered by challenges such as the shuttle effect of lithium polysulfides (LiPSs), slow sulfur redox reaction kinetics, and poor electrical conductivity. The electronic configuration of the p ‐block Bi 6p orbitals is modulated through an in situ thermally‐induced reduction strategy using lignin‐based carbon nanofibers (CNFs). This approach enables the radial gradient heterophase transformation of δ‐Bi 2 O 3 , leading to the formation of a high‐density heterojunction network composite (δ‐Bi 2 O 3 ‐O VS /Bi@CNFs) rich in oxygen vacancies (O VS ), which effectively moderates the adsorption of LiPSs and enhances the kinetics of sulfur redox reactions. Based on the δ‐Bi 2 O 3 ‐O VS /Bi@CNFs, a high‐energy‐density (377 Wh kg −1 ) pouch cell with a capacity of 1.8 Ah is fabricated and successfully used in drone flights, highlighting its potential for practical applications. This work elucidates the mechanism of in situ thermally‐induced radial‐gradient heterophase evolution of p ‐block metal oxides and the influence of 6p ‐orbital electron modulation on the sulfur redox reaction.