Three-dimensional SnS2 nanopetals for hybrid sodium-air batteries

Na-air batteries are regarded as a potential alternate to Li-air batteries due to the abundant sodium source and high theoretical energy density. However, non-aqueous Na-air battery suffers from the electrode polarization owing to the formation of insoluble discharge product, which severely limits its cyclability and performance. Herein, a high performance hybrid Na-air cell is demonstrated using a dual electrolyte (mixed aqueous and non-aqueous electrolyte) system and three dimensionally (3D) grown tin sulfide (SnS2) nanopetals based air electrode. 3D SnS2 nanopetals are synthesized by a facile solvothermal method and used as an air electrode material for hybrid Na-air battery. The vertically-grown and self-assembled ultra-thin nanosheets of 3D SnS2 nanopetals provide exposed active sites for the efficient air and electrolyte diffusion to air electrodes, resulting in high performance hybrid Na-air cell. The fabricated hybrid Na-air cell displays low overpotential gap (0.52 V), high round trip efficiency (83%), high power density (300 mW g−1) and good rechargeability up to 40 cycles. The proposed 3D SnS2 nanopetals as air electrodes can provide a robust platform for the future development of Na-air batteries and other energy storage devices.