Light-assisted delocalized electron-driven g-C3N4/NSs-based cathode catalysts for high-performance rechargeable zinc-air batteries

The sluggish multi-electron transfer kinetics of oxygen reduction and evolution reactions (ORR and OER) on the air cathode significantly reduce the energy efficiency of rechargeable zinc-air batteries (RZABs). Light-assistance is an effective approach to enhance the cathode reaction rate. However, the critical scientific issue of how photogenerated electrons regulate the interfacial electronic structure and thereby influence the behavior of reaction intermediates remains unclear, posing a challenge to achieving high-performance light-assisted RZABs. This study employs delocalized electron-rich g-C₃N₄/NSs as a model material and applies in-situ electron paramagnetic resonance (EPR) and theoretical calculations to elucidate this issue. Under light assistance, delocalized electrons from g-C₃N₄/NSs alter the surface electron distribution and charge density, reducing O₂ adsorption energy and the energy barriers of key intermediate steps, thereby markedly enhancing the adsorption and desorption behavior of O₂ and key intermediates (OH*). As a result, the constructed light-assisted aqueous RZABs demonstrate a high energy density of 1020 mWh g^-1 and exhibit excellent cycling stability at a current density of 5 mA cm^-2 (cycle life of 1400 h, discharge voltage of 1.25 V, charge voltage of 2.0 V). Additionally, the developed light-assisted flexible RZABs (FRZABs) exhibit outstanding performance with excellent adaptability to extreme conditions.