Journal of Power Sources 164 (2007) 896–904 Lead–acid bipolar battery assembled with primary chemically formed positive pasted electrode H. Karami a , M. Shamsipur b,1 , S. Ghasemi a , M.F. Mousavi a,∗,1 a Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran b Department of Chemistry, Razi University, Kermanshah, Iran Received 18 February 2006; received in revised form 15 October 2006; accepted 18 November 2006 Available online 20 December 2006 Abstract Primary chemically formed lead dioxide (PbO 2 ) 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 -PbO 2 to -PbO 2 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 6V 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. © 2006 Elsevier B.V. All rights reserved. Keywords: Chemical forming; PbO 2 ; Bipolar lead–acid battery; Conductive polyethylene; Curing; Discharge capacity; Power density 1. Introduction The increasing concern for the environmental and the pollu- tion problems caused by the vehicles, especially in large cities, have led to a worldwide interest for the development of efficient electrical and hybrid vehicles. The battery, as an autonomous energy system, is a key element in the operation of the electri- cal vehicles, due to its great influence on the final cost, range and performance of the vehicle. The characteristics of the bat- teries available in the market today impose hard restrictions to the performance of the electrical vehicles. The lead–acid battery has been a successful article of com- merce for over a century. Practical lead–acid batteries began ∗ Corresponding authors. Tel.: +98 21 88011001; fax: +98 21 88005035. E-mail addresses: mfmousavi@yahoo.com, mousavim@modares.ac.ir (M.F. Mousavi). 1 ISE member. with the research and inventions of Raymond gaston plant´ e in 1860, although batteries containing sulfuric acid or lead com- ponents were discussed earlier [1]. The advantages of lead–acid batteries include: low cost of manufacture, simplicity of design, reliability and relative safety when compared to other electro- chemical systems. Relatively good specific power has enabled the widespread use of lead–acid batteries for starting, lighting and ignition of engine (SLI) purposes for vehicular (e.g., auto- motive, marine and aviation) applications. The lead–acid system has also found widespread use as traction batteries in golf carts and boats. However, the use of lead–acid batteries for electric cars as an alternative to fossil fuels has been limited by the need for better specific energy and deep discharge cycle lifetime. The bipolar lead–acid batteries have shown increasing promise in overcoming these limitations. The on-going competition of more fuel economic cars has led to the introduction of the first hybrid electric vehicles (HEV), such as Toyota (Prius) and Honda (Insight). These high fuel 0378-7753/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2006.11.034