Gas Sensing Performance of Lead-Free Perovskite Cs ₃ Sb ₂ Cl ₉ for Monitoring Typical Electrolyte (DMC) Leakage in Lithium-Ion Batteries

Dimethyl carbonate (DMC), the primary component of lithium-ion battery (LIBs) electrolytes, is volatile at room temperature and can serve as a key indicator for detecting electrolyte leakage. In this work, leaf-like Cs₃Sb₂Cl₉ was synthesized via a single solvent solubility difference method, with its surface exhibiting strong orientation on the (110) crystal plane. The sensor demonstrated excellent gas-sensing performance toward detecting DMC (50 ppm of DMC of 3.94), with relatively short response and recovery times of 104 and 66 s, respectively (when tested 25 ppm of DMC), and a low detection limit of 100 ppb. In situ infrared spectroscopy first revealed that Cs₃Sb₂Cl₉ catalyzes the decomposition of DMC into the byproduct methanol during the adsorption process. Density functional theory (DFT) calculations further elucidated the adsorption behavior of DMC on different active sites of the Cs₃Sb₂Cl₉ (110) plane, indicating that the Sb site possesses a stronger adsorption affinity for DMC. Provides strong evidence that the B site of the perovskite serves as a highly active site. This study not only presents a preliminary exploration of Cs₃Sb₂Cl₉ in gas sensing but also provides valuable insights into the sensing mechanisms of lead-free halide perovskites.