Development and characterization of bipolar lithium composite polymer electrolyte (CPE)-FeS2 battery for applications in electric vehicles

A small laboratory prototype of a new lithium battery for electric vehicles and load levelling has been developed. This rechargeable battery consists of thin foils of lithium anode, composite solid electrolyte (CSE) or composite polymer electrolyte (CPE) and a composite FeS2 (pyrite) cathode. The battery has several advantages over other state-of-the-art polymer electrolyte batteries: (i) low-cost cathode, pyrite, is a natural ore, therefore environmentally friendly, (ii) small prototype cells exhibited very high specific energy, projected to be 140 Wh/kg at a C/6 to C/10 rate (three times larger than that of a lead/acid battery), and more than forty 100% charge/discharge cycles; (iii) this battery has an internal electrochemical overcharge protection mechanism (which is essential for bipolar batteries), and (iv) for both CSE and CPE, the Li/electrolyte interfacial resistance is low and stable up to 3000 h (CPE) and 700 h (CSE) at 120°C. The long-term projected specific energy for this battery is over 200 Wh/kg, five times larger than that of the lead/acid battery and one of the highest among all batteries in progress.