Improved Cycling Performance of Si Thin Film Anode for Lithium Rechargeable Batteries

摘要

We investigated efficient ways to improve the cycling performance of Si film electrode as an anode of Li-ion batteries. The Si films were deposited on a Cu or Ni foil by a magnetron sputtering method. In view of the fact that the improvement of the cycling performance can be achieved by preventing the electrical contact loss of active material, Si with the current collecting substrate, we proposed the approaches, the surface morphology obtained by preferential deep etching at grain boundary regions of the substrate, and the introduction of the gluing layer into the Si film/substrate interface. These trials impressively improve the cycling performance of Si film electrodes. It also appears that the current density used during cycling tests may play a crucial role in the cracking behavior of Si films. The superior cyclability is obtained by forming small and uniform microislands in Si film electrodes.