Methanothermal reduction of mixtures of PbSO4 and PbO2 to synthesize ultrafine α-PbO powders for lead acid batteries

Three artificial mixtures of PbSO 4 and PbO 2 as well as the active materials obtained directly from the positive plates of spent batteries have been solvothermally treated in methanol at 140 °C for 24 h, which produce mainly PbO·PbSO 4 . The PbO·PbSO 4 can be easily desulphated with ammonium carbonate to produce PbCO 3 , which can be calcined to form α-PbO to be used as positive active material of lead acid batteries . The α-PbO powders are irregular particles and highly electrochemically active, which discharges around 165 mAh g −1 at 5 mA g −1 , 80 mAh g −1 at 200 mA g −1 and 60 mAh g −1 at 400 mA g −1 with excellent cyclic stability in 50 cycles. SEM investigations show that the as-formed PbO·PbSO 4 may inherit and enhance the morphological characteristics of PbSO 4 , and carbonation of PbO·PbSO 4 does not destroy the rod-like characteristics. For the active material from the positive plates of spent lead acid batteries, the discharge capacities are 170 mAh g −1 at the current density of 5 mA g −1 , and 60 mAh g −1 at 400 mA g −1 , which is also similar. In 50 cycles, its capacity loss is only 5%.