Lead–acid bipolar battery assembled with primary chemically formed positive pasted electrode

Primary chemically formed lead dioxide (PbO2) was used as positive electrode in preparation of lead–acid bipolar batteries. Chemical oxidation was carried out by both mixing and dipping methods using an optimized amount of ammonium persulfate as a suitable oxidizing agent. X-ray diffraction studies showed that the weight ratio of β-PbO2 to α-PbO2 is more for mixing method before electrochemical forming. The electrochemical impedance spectroscopy (EIS) was used to investigate charge transfer resistance of the lead dioxide obtained by mixing and dipping methods before and after electrochemical forming. Four types of bipolar lead–acid batteries were produced with: (1) lead substrate and conventional electroforming; (2) carbon doped polyethylene substrate with conventional electroforming; (3) carbon doped polyethylene substrate with chemical forming after curing and drying steps in oxidant bath, followed by electrochemical forming, and (4) carbon doped polyethylene substrate with primary chemical oxidation in mixing step, followed by conventional electroforming. The capacity and cycle-life tests of the prepared bipolar batteries were performed by a home-made battery tester and using the pulsed current method. The prepared batteries showed low weight, high capacity, high energy density and high power density. The first capacities of bipolar batteries of type 1–4 were found to be 152, 150, 180 and 198 mAh g−1, respectively. The experimental results showed that the prepared 6 V bipolar batteries of type 1–4 have power density (per cell unit) of 59.7, 57.4, 78.46 and 83.30 mW g−1 (W kg−1), respectively.