Enhanced zinc storage performance of mixed valent manganese oxide for flexible coaxial fiber zinc-ion battery by limited reduction control

While manganese-based cathodes have been intensively studied for zinc-ion batteries (ZIBs), the limited rate capability and cycle life have always been a difficult problem to be solved. Here, we report a mixed valent manganese oxide (MnOx) cathode with superior electrochemical performance, which exhibits a high specific capacity of 450 mA h/g at 0.2 C and a satisfactory specific capacity of 158.3 mA h/g at a high rate of 5 C. The mixed cathode system reduces the charge transfer resistance, and show good surface stability and adsorption properties, so it is beneficial for the storage of Zn2+. Meanwhile, coaxial fiber ZIBs (CFZIBs) with splendid flexibility are assembled utilizing the elaborately prepared cathode material. The CFZIBs achieve a reversible capacity of 255.8 mA h/g and the capacity retention rate is as high as 80 % after 1000 bending deformations. This study provides new opportunities for designing ZIBs with high performance and high flexibility.