Si-O-C Composites Prepared By Electrodeposition on CNTs/Cu or Carbon Paper Substrate and Electrochemical Performance for Lithium Ion Battery

Abstract

Silicon have been attracted as promising anode material because of its higher theoretical capacity than commercial graphite (silicon: 4200 mA h g-1, graphite: 372 mA h g-1). We have been reported the novel Si-O-C composite as anode for lithium secondary batteries with high discharge capacity around of 1045 mA h (g of Si)-1 at 2000th cycle and 842 mA h (g of Si)-1 with outstanding cycle ability over 7200 cycles. Nevertheless, it is not easy to increase the thickness of Si-O-C composite for higher areal capacity due to its weak adhesion strength between Si-O-C with current corrector. To solve this problem, we reported the nickel micro-nanocones hierarchical structured (MHS) substrate and carbon nanotubes (CNTs) covered Cu substrate, and Si-O-C was deposited on those of current collectors, resulting in improved areal capacity and deposited Si amounts, 600 mA h cm-1 with Si-O-C deposited on MHS substrate and enhanced deposited Si amounts up to 16.7 % by CNTs/Cu substrate. In this research, the Si-O-C deposited on to CNTs/Cu substrate was used as anode for full-cell test with LiCoO2 (LCO) cathode. The loading amounts of LCO and Si-O-C were controlled to find optimum loading amounts for good-balanced LCO//Si-O-C full cell. Besides, to enhance the areal capacity, carbon paper (CP) which has three-dimensional structure was used as current collector. The Si-O-C/CP was prepared by electrodeposition with two kinds of electrolytes, in PC and EC/DEC bath. Material and electrochemical properties of Si-O-C/CP was measured by FE-SEM, raman spectrum, inductively coupled plasma, and charge/discharge test by half-cell. Acknowledgements This work was partly supported by “Advanced Low Carbon Technology Research and Development Program, Specially Promoted Research for Innovative Next Generation Batteries (ALCA-SPRING)” from Japan Science and Technology Agency (JST), Japan.