A deep insight into the adsorption mechanisms of lithium-ion batteries thermal runaway gases onto Cu-decorated hBN for gas sensing application using DFT

Abstract

Lithium-ion batteries, due to their environmental friendliness and high energy capacity, are extensively used in the field of transportation and energy storage. However, the problem of thermal runaway in lithium-ion batteries has become a serious threat to humans. Therefore, looking at these issues, we have investigated the adsorption mechanism of thermal runaway gases (C2H4, CO, CO2, H2, and CH4) onto pristine hBN and Cu-doped hBN using the Density Functional Theory (DFT). The adsorption of C2H4, CO, CO2, H2, and CH4 gas molecules onto pristine hBN was physisorption, resulting in poor recovery time, charge transfer, selectivity and sensitivity. However, substitutional doping of the Cu atom at the B vacancy causes thermal runaway gases to be adsorbed chemically. DOS calculation showed that the adsorption of C2H4, CO, CO2, H2, and CH4 gas molecules reduces the band gap of the Cu doped hBN, indicating chemoresistive behaviour of Cu-doped hBN. Further, various other calculations, such as charge density differences, showed that C2H4, CH4, CO, CO2 and H2 gas act as electron donors and Cu-doped hBN as electron acceptors, whereas RDG calculation confirmed that weak vdW and strong attractive type of non-covalent interaction exist in the case of pristine hBN and Cu-doped hBN, respectively. Finally, our DFT results confirmed that Cu-doped hBN exhibits enhanced sensitivity and recovery time towards thermal runaway gases, thereby making Cu-doped hBN a potential candidate to be utilized as a sensing material in gas sensors to detect thermal runaway gases.