Developing High-Performance In-Plane Flexible Aqueous Zinc-Ion Batteries with Laser-Scribed Carbon-Supported All...

Developing high-performance, safer, and affordable flexible batteries is of urgent need to power the fast-growing flexible electronics market. In this respect, zinc-ion chemistry employing aqueous-based electrolytes represents a promising combination considering the safety, cost efficiency, and both high energy and high-power output. Herein, we represent a high-performance flexible in-plane aqueous zinc-ion miniaturized battery constructed with all electrodeposited electrodes, i.e., MnO₂ cathode and zinc anode with polyimide-derived interdigital patterned laser-scribed carbon (LSC) as the current collector as well as the template for electrodeposition. The LSC possesses a cross-linked network of graphitic carbon sheet, which offers large surface area over low footprint and ensures active materials loading with a robust conductive network. The LSC with high zincophilic characteristic also offers dendrite-free zinc deposition with very low Zn²⁺ plating stripping overpotential. Benefitting from the Zn//MnO₂-rich redox chemistry, the ability of the 3D LSC network to uniformly distribute reaction sites, and the architectural merits of in-plane interdigitated electrode configuration, we report very high capacity values of ∼549 mAh/g (or ∼523 μAh/cm²) and 148 mAh/g (or 140 μAh/cm²) at 0.1 A/g (0.095 mA/cm²) and 2 A/g (1.9 mA/cm²) currents, respectively. The device was also able to maintain a high capacity of 196 mAh/g (areal capacity of 76.19 μAh/cm²) at 1 A/g (0.95 mA/cm²) current after 1350 cycles. The flexibility of the device was demonstrated in polyacryl amide (PAM) gel polymer soaked with a 2 M ZnSO₄ and 0.2 M MnSO₄ electrolyte, which exhibited a comparable specific capacity of ∼102-110 mAh/g in flat condition and different bending (100° or 160° bending) conditions. The device does not use any conventional current collector, separator, and conductive or polymer additives. The overall process is highly scalable and can be completed in less than a couple of hours.