Arabian Journal of Chemistry (Oct 2022)
Characterization of lignin and lignin-derivatives from biomass. Application as expander of Lead-acid battery
Abstract
Expanders, as lignosulfonates, are crucial for a good performance of Pb/acid batteries. In the process of discharge, the Pb and the PbO2 go to PbSO4. The formed PbSO4 is adsorbed on the surface of the Pb electrode and dramatically reduces the lifetime of the battery by the formation of big PbSO4 crystals. In order to prevent that, the addition of expanders in the negative electrode is an economic solution to prevent the formation of big crystals. In this investigation, we propose the synthesis of several lignosulfonates obtained from lignin of many biomass origins. We have derivatized nine samples of lignin via microwave-assisted sulfonation, then we have characterized how efficient is the chosen synthesis method. The lignosulfonates obtained have been characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (1HNMR), two-dimensional correlated spectroscopy (COSY), and elemental analysis to acquire some relevant information about their structure in terms of functional groups. In this way, three commercial lignosulfonates, Vanisperse A, Indulin AT, and Oakwood, have been selected as references for our comparisons. Moreover, we have checked their electrochemical properties, using electrochemical techniques to compare their behavior with respect to the commercial lignosulfonates. Finally, we have selected one of them and we have tested its performance as an expander in a Pb/acid battery. That result is a very promising first approach, and we can conclude that lignosulfonates derivatives are a good and low-cost choice to improve the lifetime of Pb/acid batteries. In particular, it is shown that the incorporation of LignosB improves the cell formation as well as the first capacity (36.30% more) and the charge acceptance (63.16% more), being these relevant parameters in the performance of Pb/acid batteries.
