NiCoO Nanowires Immobilized on Nitrogen-Doped TiCT for High-Performance Wearable Magnesium-Air Batteries.

Flexible magnesium (Mg)-air batteries provide an ideal platform for developing efficient energy-storage devices toward wearable electronics and bio-integrated power sources. However, high-capacity bio-adaptable Mg-air batteries still face the challenges in low discharge potential and inefficient oxygen electrodes, with poor kinetics property toward oxygen reduction reaction (ORR). Herein, spinel nickel cobalt oxides (NiCoO) nanowires immobilized on nitrogen-doped TiCT (NiCoO/N-TiCT) are reported via surface chemical-bonded effect as oxygen electrodes, wherein surface-doped pyridinic-N-C and Co-pyridinic-N moieties accounted for efficient ORR owing to increased interlayer spacing and changed surrounding environment around Co metals in NiCoO. Importantly, in polyethylene glycol (PVA)-NaCl neutral gel electrolytes, the NiCoO/N-TiCT-assembled quasi-solid wearable Mg-air batteries delivered high open-circuit potential of 1.5 V, good flexibility under various bent angles, high power density of 9.8 mW cm, and stable discharge duration to 12 h without obvious voltage drop at 5 mA cm, which can power a blue flexible light-emitting diode (LED) array and red smart rollable wearable device. The present study stimulates studies to investigate Mg-air batteries involving human-body adaptable neutral electrolytes, which will facilitate the application of Mg-air batteries in portable, flexible, and wearable power sources for electronic devices.