The energy-dispersive X-ray spectroscopy (EDS) was conducted on anode and cathode active materials for examining sulfur content which is represented as the Pb/S ratio. The Pb/S is the ratio of composition obtained from the Pb, PbO₂ and PbSO₄peaks in EDS spectrum (Table 2). Higher values of Pb/S means lower SO₄^2- content and vice versa. The Pb/S ratio indicative of the relative amount of sulfate (SO₄^2-) getting deposited on anode and cathode after cycling. Pb/S ratio of the fresh cell is significantly different due to complete reversibility of PbSO₄ to Pb as compared to that observed in cycled cells. As indicated from Pb/S ratio it can be seen that SO₄^2-deposition and hardening were higher in anode and cathode in discharged state which eventually led to reduction in the amount of active materials with cycling (130 cycles).^21,22,24 It can be seen that SO₄^2- content increases with decreasing temperature from 40 to 0 °C due to slower kinetics and lower PbSO₄ reversibility to Pb. However, it is lowest at -10 °C as compared to cycled and fresh cells essentially due to reduced active material (~50%) availability as seen from the charge-discharge characteristics (Figures 3-5).^6,18,25