Zwitterionic Gel Electrolyte Stabilized Multivalent Tellurium Redox for High‐Energy Lithium Batteries

Abstract

ABSTRACT Lithium batteries based on multivalent chalcogen conversion chemistries offer a promising route toward high‐energy, practical energy storage, but their development is impeded by the limited accessibility and instability of high‐valence intermediates. Here we report a quasi‐solid‐state lithium||tellurium battery in which a zwitterionic gel polymer electrolyte (GPE) stabilizes multivalent tellurium redox, enabling reversible six‐electron conversion under practical conditions. By embedding LiCl directly into a Te cathode, we establish a Te/LiCl composite that activates the sequential Te 2 − /Te 0 /Te 2+ /Te 4+ redox cascade with three well‐defined discharge plateaus at 2.42, 2.17, and 1.76 V. This multivalent conversion delivers a high specific capacity of 938 mAh g − 1 and an energy density of 619 Wh kg − 1 based on the whole cathode. To suppress dissolution and decomposition of high‐valence Te n+ species, we design a zwitterionic GPE that provides dual‐ion (Li + /Cl − ) transport, robust Li metal compatibility, and effective confinement of soluble intermediates. The resulting quasi‐solid Li||Te/LiCl cells exhibit excellent rate performance and long‐term durability (87.6% capacity retention after 400 cycles at 1 A g − 1 ), and achieve an areal capacity of 5.4 mAh cm − 2 . This work establishes a zwitterion‐stabilized, multivalent Te redox platform that bridges high energy density with practical cycling stability, offering a generalizable strategy for advanced conversion‐type lithium batteries.