Novel Composite Thick-Film Electrodes Consisted of Zinc Oxide and Silicon for Lithium-Ion Battery Anode

As a novel anode for Li-ion battery, ZnO/Si composite thick-film electrodes with various ratios of ZnO:Si were prepared by a gas-deposition method using a commercial Si powder and a radial-shaped ZnO powder synthesized by a precipitation method. We investigated the effect of the ZnO amount and the radial morphology on the anode performance, comparing with charge-discharge properties of a ZnO electrode without Si. The ZnO electrode showed a stable cyclability and a moderate discharge capacity of 160-220 mA h g(-1) after the 20th cycle. The composite electrode of ZnO/Si with a ratio of 89/11 wt.% exhibited a good cycle stability after the 20th cycle and large discharge capacities exceeding the theoretical capacity of graphite until the 370th cycle. In contrast, a composite electrode containing of crushed ZnO showed a flat surface and poor performance. These results revealed that microstructure of the radial-shaped ZnO is very favorable for improving efficiencies of electrode reactions due to its high surface area, and is effective in accommodating the stresses induced by Li-insertion and Li-extraction in/from Si.