Comparison of the Adsorption Characteristics and Sensing Performance of MoS₂, MoSe₂, and Janus MoSSe toward Lithium-Ion Battery Thermal Runaway Gases.

This study employs density functional theory to investigate the adsorption and sensing behaviors of characteristic decomposition gases from lithium-ion battery thermal runaway (CO, CO₂, and C₂H₄) on pristine and Ag-cluster modified MoS₂, MoSe₂, and Janus MoSSe monolayers. The structural, electronic, and adsorption properties were systematically analyzed to elucidate the influence of Agn (n = 1-3) clusters on the gas sensing performance. Results indicate that Ag doping enhances the thermodynamic formation energy, charge transfer, and electronic coupling between gas molecules and substrates, converting weak physisorption into stronger chemisorption, particularly for CO and C₂H₄. Among all configurations, Ag₃-MoSSe exhibits the highest adsorption energy and the most significant modulation of the Fermi level, accompanied by band gap narrowing and improved conductivity. Coadsorption of CO and C₂H₄ demonstrates a synergistic effect, leading to quasi-metallic characteristics and stronger hybridization between the Ag-4d and C-2p orbitals. Furthermore, the weak interaction of H₂O with the Ag-modified surfaces indicates good humidity resistance and selectivity. Work function and sensitivity analyses reveal that Ag₃-MoSSe possesses the highest sensitivity to C₂H₄ with moderate recovery capability, making it a promising candidate for real-time detection of characteristic gases generated during lithium-ion battery thermal runaway.