According to project leader Yongsheng HU, the design is based on copper and iron-based oxide as anode, anthracite-based soft carbon as cathode, and presently reaches an energy density of 100 Wh/kg. This is less than a lithium-ion battery, but twice the energy density of lead-acid batteries. Cycle numbers have reached more than 500 times, better than lead-acid batteries, with an energy conversion efficiency of up to 90% and good low temperature performance (-20 ℃ discharge capacity is 86% of room discharge capacity). Material cost is about 40% lower than for lithium-ion batteries. The project group aims at 5000 cycle numbers, following the existing lithium-ion battery production processes and equipment, without a separate stove. It is expected that in future sodium-ion batteries can gradually replace lead-acid batteries and be used in low-speed electric vehicles, as a complementary solution to lithium-ion batteries.

CAS news release, February 17, 2017