Dilute electrolyte-heterostructure interlocking regulates the amorphization conversion of Te cathodes for durable aqueous batteries

Abstract

Tellurium-based aqueous batteries (TeABs) promise high theoretical capacity but are constrained by sluggish Te⁰/Te⁴⁺ conversion and rapid capacity fading. Here, we introduce a dilute electrolyte–heterostructure interlocking (DEHI) strategy that couples a Te/ZnSe (TZS) heterostructure with a dilute ammonium-acetate electrolyte to trigger and sustain the reversible Te ↔ amorphous TeO₂ (a-TeO₂) conversion. Thermodynamically, the dilute ammonium-acetate medium uniquely favors deep, reversible amorphization compared with alternative salts or pH-controlled counterparts. Kinetically, the TZS interface provides a strong built-in electric field, accelerates charge transport, and enhances interfacial H₂O adsorption. Moreover, various ex situ experimental characterization studies and theoretical calculations show that neither the dilute electrolyte nor the heterostructure alone yields reversible Te ↔ a-TeO₂, underscoring their interlocking effects. As a result, TZS exhibits outstanding high-rate cyclability, sustaining a remarkable specific capacity of 158.6 mA h g⁻¹ over 1000 cycles at an unprecedented current density of 10 A g⁻¹ with near-unity coulombic efficiency. In addition, TZS‖Zn full cells demonstrate robust rate capability (206.7 mA h g⁻¹ at 10 A g⁻¹) and durable cycling (249.0 mA h g⁻¹ at 2 A g⁻¹ after 200 cycles). The DEHI concept offers a practical pathway to reconcile thermodynamics and kinetics in conversion-type aqueous Te-based cathodes, thereby advancing the applicability of TeABs for stationary energy storage.