Sn-SnSb Filled Carbon Fiber Anodes for High Energy Density Lithium Ion Batteries

An advanced material that exploits the excellent cycle life of a carbon fiber and the high gravimetric and volumetric capacity of the tin-based system is being proposed as a composite anode in lithium-ion batteries. Carbon fiber will be subjected to mild oxidation under oxygen so as to generate nano pores that will be subsequently filled by intermetallic materials SnSb using a sol-gel approach. The SnSb alloy in the porous carbon matrix is expected to be in the form of a nanofiber which is desirable for high rate capability and extended cycling. The carbon fiber will act not only as an electronic conductor but also as a cushion that will accommodate the volume changes during lithium intercalation and deintercalation. This composite anode when combined with a higher capacity cathode material LiCoxNiyAlzO2 should lead to energy density in excess of 230 Wh/Kg. These attributes of this proposed technology will definitely fulfill the battery requirements for space applications where cycle life of more than 30000 cycles for low earth orbit (LEO), high rate applications (> 4 kW/kg) and rapid charge/discharging (ten of seconds) and calendar life of more than 10 years for geosynchronous orbits (GEO) are needed.