The in-situ growth of Cu2O–CuO on Cu foam coated with carbon derived from polydopamine as the flexible high-voltage cathode for thermal batteries

Thermal batteries are a type of thermally activated reserve battery, where the cathode material significantly influences the operating voltage and specific capacity. In this work, Cu 2 O–CuO nanowires are prepared by in-situ thermal oxidation method onto Cu foam, which are further coated with a carbon layer derived from polydopamine (PDA). The morphology of the nanowires has been examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The material shows a kind of core–shell structure, with CuO as the shell and Cu 2 O as the core. To further explore the interaction between the material and lithium-ion (Li + ), the Li + adsorption energies of CuO and Cu 2 O were calculated, revealing a stronger affinity of Li + for CuO. The unique core–shell nanowire structure of Cu 2 O–CuO can provide a good Li + adsorption with the outer layer CuO and excellent structural stability with the inner layer Cu 2 O. When applied in thermal batteries, Cu 2 O–CuO–C nanowires exhibit specific capacity and specific energy of 326 mAh g −1 and 697 Wh kg −1 at a cut-off voltage of 1.5 V both of which are higher than those of Cu 2 O–CuO (238 mAh g −1 and 445 Wh kg −1 ). The discharge process includes the insertion of lithium ions and subsequent reduction reactions, ultimately resulting in the formation of lithium oxide and copper. The in-situ synthesis of copper oxide nanowires through high-temperature thermal oxidation, combined with the development of PDA-coated Cu 2 O–CuO composite flexible electrodes, offers a promising advancement for high-performance cathodes in next-generation thermal batteries. • Core-shell Cu 2 O-CuO nanowires provide exceptional Li + adsorption and structural stability, enabling high-performance thermal battery operation at elevated temperatures. • PDA-derived carbon coating boosts electrical conductivity, enhancing initial voltage and prolonging discharge duration. • Integrated molding prevents high-temperature fracturing seen in traditional powders, ensuring stable discharge behavior.