Microemulsion synthesis of 3D flower-like calcium zincate anode materials with superior high-rate and cycling property for advanced zinc-based batteries

A new kind of 3D hierarchical flower-like calcium zincate is successfully achieved by a simple microemulsion method. The obtained sample is constructed with many interconnected rhomboid calcium zincate nanosheets with a thickness of 80–100 nm. When served as anode active material for zinc-based battery, the as-prepared calcium zincate delivers superior high-rate properties and improved cycling stability. At 2, 5, 10, 15, 20C, the flower-like calcium zincate shows higher specific discharge capacities of ～297.7, ～254.6, ～232.5, ～202.8 and ～170.5 mAh g−1, respectively, which are significantly higher than those of the conventional hexagon and rhomboid calcium zincate. Especially, after 400 cycles at 1C/1C, the flower-like CZO achieves a capacity retention of 90.8%, whereas the values for the hexagon and rhomboid samples are only 70.2% and 54.7%, respectively. The pronounced high-rate and cycling properties are attributable to its unique 3D hierarchical flower-like structure and small particle size, which leads to the reduced charge transfer resistance, enhanced reversibility, and improved structural stability. Therefore, the proposed 3D hierarchical flower-like calcium zincate is promising anode material with excellent high-rate and cycling properties for advanced zinc-based rechargeable batteries.