Abstract
Renewable energy storage is a key issue in our modern electricity-powered society. Lead acid batteries (LABs) are operated at partial state of charge in renewable energy storage system, which causes the sulfation and capacity fading of Pb electrode. Lead-carbon composite electrode is a good solution to the sulfation problem of LAB. In this paper, a rice-husk-derived hierarchically porous carbon with micrometer-sized large pores (denoted as RHC) has been used as the component of lead-carbon composite electrode. Scanning electron microscopy was used to characterize the morphology of lead-carbon composite electrode. Electrochemical impedance spectroscopy was used to determine the charge transfer capability of lead-carbon composite electrode. Both full charge-discharge method and charge-discharge method operating at harsh partial state of charge condition have been used to prove the superior energy storage capability of lead-carbon composite electrode. Experiment results prove that the micrometer-sized pores of RHC are beneficial to the construction and stability of lead-carbon composite electrode. Microporous carbon material with high surface area is not suitable for the construction of lead-carbon electrode due to the ruin of lead-carbon structure caused by severe electrochemical hydrogen evolution.
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•Carbon materials derived from rice husk (RHC) have large pores.•RHC has good effect on inhibiting sulfation of lead negative electrode.•Carbon material with high surface area has opposite effect on lead-carbon electrode.•Significance of pore size of carbon in lead-carbon is discussed.