A new composite cathode for high-performance lithium–polymer batteries

Low-molecular-weight poly(ethyleneglycol) was tested as lithium-ion conductive matrix in a crystalline V2O5-based composite cathode. To assess the feasibility of this composite cathode in solid-state rechargeable batteries, the ion transport properties, the chemical stability and the electrochemical stability were evaluated. The cathode exhibited fairly good electrochemical properties at a moderately high temperature. At 338 K, a 7Li diffusion coefficient of about 6.8×10−8 cm2 s−1 was measured. The cathode showed good thermal and electrochemical stability. Battery cells were assembled and their performance was evaluated at 338 K and at different discharge rates. About 270 mAh g−1 (corresponding to 1.8 lithium equivalents) were delivered when cycling the battery at a low discharge rate (0.04 mA cm−2, C/24). The active material utilization decreased with increasing discharge rate. About 1.0 lithium equivalents were cycled at 0.270 mA cm−2and only 0.33 at 0.480 mA cm−2.