A highly efficient cathode catalyst γ-MnO2@CNT composite for sodium-air batteries

The γ-MnO 2 @CNT catalyst was prepared by in situ solid phase synthesis and first applied into sodium-air batteries (SABs). The initial discharge specific capacity of SABs with γ-MnO 2 @CNT catalyst can reach 8804 mA h g −1 and the overpotential gap is only 140 mV, which is better than the batteries that is catalyzed by α-MnO 2 @CNT and pure CNT. Besides, the batteries also exhibit excellent cycle performance, which can keep relatively stable for 246 cycles at 500 mA g −1 and 140 cycles at 1000 mA g −1 .