Electrochemical energy storage characteristics of CaB6

•CaB6 was charge-discharge tested in 1 m LiPF6.•The material showed a rate capability of 2.5 A/g.•CaB6 showed an order of magnitude higher diffusivity for lithium than titanate.•The specific capacitance was 35 F/g which can be enhanced by modulating the structure.

CaB6 has a tunneled framework lattice structure that is suitable for intercalation of ions. Electrochemical charge-discharge testing of CaB6 in lithium containing non-aqueous electrolyte showed a specific capacitance of 35.7 F/g at 0.42 A/g current rating. Even though the specific capacitance was low, CaB6 shows promise as a Li-ion intercalating material because of its higher diffusivity (3×10−10 cm2/s), p-type semiconductivity, high conductivity, and low density.