2017 Volume 85 Issue 6 Pages 310-314
We have previously reported that the oxygen vacancies of tungsten oxide (WO3) play an important role in determining the charge/discharge rate of lithium ion secondary batteries (LIBs). We have fabricated electrodes by spray-coating WO3 particles onto a Ti foil, then generating oxygen vacancies and inducing necking between the particles by annealing in N2. However, this conventional method is unsuitable for use in mass production because the adhesive strength between the particles and the foil is decreased by the stress generated during heat treatment and because of the high cost of the Ti foils. In this study, with the goal of enabling the mass production of electrodes, we propose a method of synthesizing WO3 particles, in which oxygen vacancies are generated before coating to form electrodes on Al foil. A synthesized mixed layer containing WO3 particles and a conductive auxiliary agent was coated on a carbon-coated Al foil to obtain a negative electrode for LIBs. As a result, an internal resistance of 3.7 Ω·cm2 was obtained. Furthermore, evaluation of the discharge rate revealed that the capacity retention rate was 65.7% at 100 C (100% at 1 C). We succeeded in fabricating the above electrodes with high-speed charge/discharge characteristics.
