Adsorption and gas-sensitive properties of Pb and Rh doped GaNNT for lithium battery thermal runaway gases: A DFT study

The gas-sensitive technology for detecting thermal runaway gases during lithium-ion battery thermal runaway is feasible. We performed DFT calculations to analyze the adsorption energy (E_ads), density of states (DOS), band structure, differential charge density (DCD), and frontier molecular orbitals of Pb and Rh-doped GaN nanotubes (M-GaNNT) with respect to four main gases (CH₄, CO, CO₂, H₂). Rh-GaNNT exhibits the most substantial band gap modification, with an average change of 139.9 %, while Pb-GaNNT shows an average alteration of 28.8 %. By analyzing E_ads, sensitivity response, and recovery time of M-GaNNT, we predicted its potential applications in gas-sensing devices and adsorbents. Notably, Pb-GaNNT demonstrates exceptional CO detection performance at 398 K, with an ultra-fast recovery time of 0.13 s, strong adsorption energy of −1.232 eV, and remarkable sensitivity of 2.44 × 10⁷. Similarly, Rh-GaNNT performs outstanding CH₄ sensing characteristics at 498 K, featuring rapid recovery (τ = 0.43 s), substantial adsorption energy (E_ads = −1.150 eV), and extremely high sensitivity (SR = 1.19 × 10¹⁹). Furthermore, the materials exhibit superior gas removal efficiency under other temperatures conditions for all four target gases. These findings highlight the potential of metal-doped GaNNTs as high-performance sensing materials for lithium-ion battery safety monitoring systems.