“…Being similar to (PbCO 3 ) 2 Á Pb(OH) 2 and CuCO 3 Á Cu(OH) 2 , NiCO 3 Á 2Ni(OH) 2 Á 4H 2 O delivers a discharge capacity of 1742.6 mAh g À 1 in the first cycle, which is much higher than the theoretical value (427.7 mAh g À 1 ). The extra capacity should correspond to the growth of SEI film on the surface of the active particles and the probable lithium storage on interface in the initial discharge process [29,30]. After 20 cycles, the discharge and charge capacities are maintained at 104.3 and 98.1 mAh g À 1 , respectively.…”