Anti-catalytic and zincophilic layers integrated zinc anode towards efficient aqueous batteries for ultra-long cycling stability

Aqueous zinc-based battery is usually plagued by serious dendrites and side reactions including Zn corrosion and water decomposition on the anode. To address the drawbacks, constructing coating layers with high conductivity and anti-catalytic effects on hydrogen evolution reaction has been considered as an efficient strategy. Herein, cheap and abundant two-dimensional (2D) conductive graphite (KS-6) coating layer with high electronic conductivity (~ 10⁶ S·m⁻¹) could directly form strong bonding with Zn foil due to high zincophilicity, which correspondingly protects Zn metal from liquid electrolyte to inhibit parasitic hydrogen evolution and guide uniform Zn electrodeposition during cycling. The KS-6 layer owns a profitable charge redistribution effect to endow Zn anode with a lower nucleation energy barrier and a more uniformly distributed electric field compared with bare Zn. Therefore, such integrated Zn anode exhibits low voltage hysteresis (~ 38 mV) and excellent cycling stability with dendrite-free behaviors (1 mA·cm⁻² and 2 mAh·cm⁻²) over 2,000 h, far outperforming many reported Zn metal anodes in aqueous systems. Encouragingly, in light of the superior Zn@KS-6 anode, VNO_x powders and Prussian blue analogs Mn₂Fe(CN)₆ are applied as the cathode materials to assemble full batteries, which show remarkable cycling stabilities and high Coulombic efficiencies (CEs) over 200 cycles with capacity retention of 81.5% for VNO_x//Zn@KS-6 battery and over 400 cycles with capacity retention of 94.6% for Mn₂Fe(CN)₆//Zn@KS-6 battery, respectively.