Mitsui Kinzoku Develops Si Negative Electrode for Lithium Ion Battery

Mitsui Mining & Smelting announced on Thursday the firm developed new silicon based negative electrode for lithium ion battery. The firm succeeded to develop the material with longer life. The firm tries to commercialize the material as early as 2010 through cooperation with lithium ion battery makers. The firm expects the output volume could reach monthly 200,000 units for cell phone expanding the business to annual 100 billion yen sales in future. The firm developed the material, SILX with around double storage capacity compared with carbon graphite. With SILX, lithium ion battery’s energy efficiency improves by 30-50% from current carbon graphite. The firm developed the method to coat silicone with copper film with 0.2-0.3 micrometers to prevent expansion of silicone, which causes shorter life. The firm keeps developing mass production technology along with combination with positive electrode for commercialization through cooperation with battery makers. Lithium ion battery application expands to electric tool along with traditional cell phone, laptop computer and digital camera. Hybrid vehicle application is limited due to limited output power of carbon graphite.