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

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 -}/Te⁰/Te²⁺/Te⁴⁺ 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 Teⁿ⁺ 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.