Novel synthesis and electrochemical investigations of ZnO/C composites for lithium-ion batteries

摘要

For the first time, ZnO/C composites were synthesized using zinc glycerolate as a precursor through one-step calcination under a nitrogen atmosphere. The effect of the heat treatment conditions on the structure, composition, morphology as well as on the electrochemical properties regarding application in lithium-ion batteries are investigated. The products obtained by calcination of the precursor in nitrogen at 400-800 degrees C consist of zinc oxide nanoparticles and amorphous carbon that is in-situ generated from organic components of the glycerolate precursor. When used as anode material for lithium-ion batteries, the as-prepared ZnO/C composite synthesized at a calcination temperature of 700 degrees C delivers initial discharge and charge capacities of 1061 and 671 mAh g(-1) at a current rate of 100 mA g(-1) and hence 1.5 times more than bare ZnO, which reaches only 749/439 mAh g(-1). The native carbon improves the conductivity, allowing efficient electronic conductivity and Li-ion diffusion. By means of ex-situ XRD studies a two-step storage mechanism is proven.