Surface microenvironment regulation of nitrogen-doped carbon via deep eutectic solvent for enhanced oxygen reaction kinetics in zinc-air batteries

Nitrogen-doped carbon (NC) is regarded as a highly promising alternative to costly platinum-based catalysts for catalyzing efficient and stable oxygen reduction reactions (ORR) to enhance the performance of zinc-air batteries (ZABs). However, the insufficient intrinsic catalytic activity of the NC restrict the ORR kinetics, thereby limiting the actual performance of ZABs. Herein, the NC was surface modified with Li-based deep eutectic solvent (DES) with low spatial site resistance to obtain Li-based NC catalyst (Li-NC). The Li-based DES adsorbed on the surface of NC by the hydrogen bonding to regulate the surface microenvironment and hydrophicity of the NC, thereby accelerating the ORR kinetics. The Li-NC exhibited a high half-wave potential (0.871 V) compared to NC (0.852 V). The ZAB with Li-NC demonstrated a great power density (158.5 mW cm⁻²) and excellent specific capacity 736.15 mA h g⁻¹), superior to that of NC (122.5 mW cm⁻² and 696.32 mA h g⁻¹). Moreover, the charging and discharging cycle time of the zinc-air battery with Li-NC was 685 h. The surface microenvironment modification with DES provides an effective strategy to improve the oxygen reactivity kinetics of NC catalysts, with great significance for future practical or commercial applications.