Wearable Textile‐Based Co−Zn Alkaline Microbattery with High Energy Density and Excellent Reliability

Abstract Wearable in‐plane Zn‐based microbatteries are considered as promising micropower sources for wearable electronics due to their high capacity, low cost, high safety, and easy integration. However, their applications are severely impeded by inadequate energy density arising from unsatisfactory capacity of cathode and poor cycling stability caused by degradation of electrode materials and Zn dendrite. Additionally, the short‐circuit induced safety issue caused by Zn dendrite is still a roadblock for Zn‐based microbatteries. Herein, a textile‐based Co−Zn microbattery with ultrahigh energy density and excellent cycling stability is demonstrated. Benefiting from the fast electron transport of three‐dimensional (3D) porous Ni‐coated textile and synergistic effect from the hierarchical Co(OH) 2 @NiCo layered double hydroxide (LDH) core−shell electrode, the fabricated Co−Zn microbattery with high flexibility delivers superior energy/power densities of 0.17 mWh cm −2 /14.4 mW cm −2 , outperforming most reported micro energy storage devices. Besides, the trench‐type configuration as well as the 3D porous Zn@carbon clothes can avoid the short‐circuit‐induced safety issues, resulting in excellent cycling stability (71% after 800 cycles). The unique core−shell structure and novel configuration provide a brand‐new design strategy for high‐performance wearable in‐plane microdevices.