Carbon Coated SnO2 as a Negative Electrode Additive for High Performance Lead Acid Batteries and Supercapacitors

Abstract

Sulfation at the negative electrode and grid corrosion at the positive electrode are the major failure modes of lead-acid batteries. To overcome the issues of sulfation, we synthesize carbon coating onto SnO2 as a negative electrode additive for lead-acid batteries. 0.25 wt% of carbon-SnO2 additive into the negative active material reduces formation cycle from 3 cycles to 1 cycle and 60% increment in capacity during the 1st cycle compare to conventional lead-acid cell. The additive cells also deliver 300 deep charge-discharge cycles at C/5 rate and >60% increase in capacity at 2C rate in relation to conventional lead-acid cells. The enhancement in capacity at all C rates and improvement in cycling is due to carbon coating which enhances the conductivity and charge storage property of negative active material. Carbon-SnO2 occupies in the pores of negative active material, restricts the growth of PbSO4 and decreases hydrogen evolution, thereby improves charge acceptance. Besides, the additive cells show 300% increase in high rate partial state of charge cycles compare to conventional lead-acid cells. The specific capacitance of carbon coated SnO2 in 4.5 M H2SO4 is 150 F g−1, at 2A g−1 with >90% capacity retention after 2000 cycles.