Coordination Reconstruction and In Situ Chemical Oxidation Bypass Generation Enabling High‐Voltage Aqueous Zn‐Te Batteries

ABSTRACT Aqueous Zn‐Te batteries offer high capacity via a six‐electron TeO 2 /Te/ZnTe reaction, yet suffer from low discharge voltage (∼0.6 V) due to the sluggish conversion kinetics and high overpotential of TeO 2 /Te. Although Cl − enables a lower‐overpotential TeCl 4 /Te conversion, the TeCl 4 hydrolysis leads to an unstable high‐voltage discharge plateau at ∼1.2 V. Besides, the accumulation of poorly conductive tellurium halide along charge hinders electron transport between the reaction zone and current collector, leading to inefficient electrochemical oxidation of Te. Here, based on the hard‐soft acid‐base (HSAB) principle, a borderline base Br − is introduced to reconstruct the coordination of the soft acid Te 4+ to form more stable phases and prevent voltage degradation. Meanwhile, Br 3 − is in situ generated via deep charging, which unlocks a chemical oxidation bypass for Te with facile electron transfer at the solid/electrolyte interface. This improves the oxidation efficiency of Te and increases the proportion of high‐voltage plateau capacity during subsequent discharge. A low‐content polyvinyl pyrrolidone addition further improves the capacity retention through its adsorption effect. Accordingly, the Zn‐Te battery delivers high capacities of 837 mAh g −1 at 0.5 A g −1 and 483 mAh g −1 at 5 A g −1 , with more than half capacity stably contributed by the high‐voltage plateau.