Modified titanium foil's surface by high temperature carbon sintering method as the substrate for bipolar lead-acid battery

Titanium foil can be a type of ideal material as the substrate for bipolar lead-acid battery. However, it can't be directly used because it can be oxidized in the high voltage and strong oxidizing conditions. In this paper, we coat the titanium suboxide on the titanium foil surface by means of the high temperature carbon sintering method for the improvement of corrosion resistance of titanium metal and use it as the substrate to bipolar lead-acid battery to study its effect on the battery performances. Modified titanium foils are characterized by SEM, XRD, corrosion resistance test and electronic conductivity test. The electrochemical properties of the bipolar lead-acid battery are investigated by constant current charge/discharge method. The results demonstrate that the titanium foil carbon-sintered at 800 °C for 2 h has the most excellent chemical stability and electronic conductivity. Initial specific capacities of positive active material of bipolar lead-acid battery with modified titanium as the substrate at 0.25C, 0.5C, 1C and 2C discharge rate are 99.29 mAh g^-1, 88.93 mAh g^-1, 77.54 mAh g^-1, and 65.41 mAh g^-1. After 50 cycles, the specific capacity of positive active material at 0.5C is 81.36 mAh g^-1and after 100 cycles, the specific capacity at 1C is 61.92 mAh g^-1.