A new water-soluble elastomer from ZEON Corp. was evaluated as binder with LiFePO4 cathode material in Li-ion batteries. The mechanical characteristic of this cathode was compared to that with PVdF-based cathode binder. The elastomer-based cathode shows high flexibility with good adhesion. The electrochemical performance was also evaluated and compared to PVdF-based cathodes at 25 and at 60°C. A lower irreversible capacity loss was obtained with the elastomer-based cathode, however, aging at 60°C shows a comparable cycle life to that observed with PVdF-based cathodes. The LiFePO4–WSB at high rate shows a good performance with 120mAhg−1 at 10C rate at 60°C.