High-performance Zn microbattteries based on a NiCo-LDH@ITO nanowire/carbon cloth composite

Following the fast growth of micro-energy storage devices, there is an urgent need to develop miniaturized electronic devices with excellent performance that are both green and safe. Planar interdigitated rechargeable Zn microbatteries (MBs) have gained widespread attention in recent years due to their ease of series-parallel integration, mechanical flexibility and no need for traditional separators. We prepared a patterned cathode of NiCo layered double hydroxide (LDH)@indium tin oxide (ITO) nanowires (NWs) @carbon cloth (CC) by the chemical vapor deposition of ITO NWs on the carbon fibers in a CC, laser patterning, and finally the electrodeposition of NiCo-LDH to coat the ITO NW@carbon fibers. The cathode was combined with a patterned Zn foil anode to form a planar MB. Because of the highly conductive ITO NWs@CC current collector, the interdigitated MB had a satisfactory performance. The planar MB has a high specific capacity of 453.5 mAh g⁻¹ (corresponding to 0.56 mAh cm⁻²) in an alkaline water-based electrolyte at 1 mA cm⁻². After 4 000 cycles the capacity increased to 216% of the initial value due to gradual penetration of electrolyte into the three-dimensional NiCo-LDH@ITO NW@CC network. It also had excellent energy (798.4 μWh cm⁻², corresponding to 649.9 Wh kg⁻¹) and power densities (4.1 mW cm⁻², corresponding to 3 282.7 mW kg⁻¹). Furthermore, MBs connected in series-parallel in lighting tests illustrate the excellent performance of the device. Therefore, these fast and simple Zn MBs with an in-plane interdigital structure provide a reference for next-generation high-performance, environmentally-friendly, and scalable planar micro-energy storage systems.