High Cycle Stability of Hybridized Co(OH)2 Nanomaterial Structures Synthesized by the Water Bath Method as Anodes for Lithium-Ion Batteries.

Cobalt oxides have been intensely explored as anodes of lithium-ion batteries to resolve the intrinsic disadvantages of low electrical conductivity and volume change. However, as a precursor of preparing cobalt oxides, Co(OH)2 has rarely been investigated as the anode material of lithium-ion batteries, perhaps because of the complexity of hydroxides. Hybridized Co(OH)2 nanomaterial structures were synthesized by the water bath method and exhibited high electrochemical performance. The initial discharge and charge capacities were 1703.2 and 1262.9 mAh/g at 200 mA/g, respectively. The reversible capacity was 1050 mAh/g after 150 cycles. The reversible capability was 1015 mAh/g at 800 mA/g and increased to 1630 mAh/g when driven back to 100 mA/g. The electrochemical reaction kinetics study shows that the lithium-ion diffusion-controlled contribution is dominant in the energy storage mechanism. The superior electrochemical performance could result from the water bath method and the hybridization of nanosheets and nanoparticles structures. These hybridized Co(OH)2 nanomaterial structures with high electrochemical performance are promising anodes for lithium-ion batteries.