Engineering electro-crystallization orientation and surface activation in wide-temperature zinc ion supercapacitors

Matching the capacity of the anode and cathode is essential for maximizing electrochemical cell performance. This study presents two strategies to balance the electrode utilization in zinc ion supercapacitors, by decreasing dendritic loss in the zinc anode while increasing the capacity of the activated carbon cathode. The anode current collector was modified with copper nanoparticles to direct zinc plating orientation and minimize dendrite formation, improving the Coulombic efficiency and cycle life. The cathode was activated by an electrolyte reaction to increase its porosity and gravimetric capacity. The full cell delivered a specific energy of 192 ± 0.56 Wh kg^-1 at a specific power of 1.4 kW kg^-1, maintaining 84% capacity after 50,000 full charge-discharge cycles up to 2 V. With a cumulative capacity of 19.8 Ah cm^-2 surpassing zinc ion batteries, this device design is particularly promising for high-endurance applications, including un-interruptible power supplies and energy-harvesting systems that demand frequent cycling.