Room Temperature DMC Gas Sensors Based on RhCu Nanoalloys Decorated WO3 Nanorods for Portable and Wireless Monitoring of LIB Electrolyte Leakage

Abstract Dimethyl carbonate (DMC) is widely recognized as an early indicator of lithium-ion battery (LIB) electrolyte leakage, making the development of a DMC gas sensor crucial. However, DMC gas sensors remain rare, and nearly all reported devices require high-temperature operation. In this study, RhCu@WO3 sensing films with varying RhCu loadings (0.3, 0.5, and 0.7 wt %) were successfully synthesized via a hydrothermal method, and their gas-sensing performance was systematically evaluated at room temperature. The results show that RhCu alloys are uniformly loaded onto the surface of monoclinic WO3 nanorods. Among them, the 0.5RhCu@WO3 sensor exhibits a response as high as 374.8% toward 100 ppm DMC at 25 °C, which is 11.1 times higher than that of pure WO3, It also shows rapid response and recovery times of 22 and 18 s, respectively, demonstrating excellent sensing performance. Furthermore, the sensor exhibits excellent selectivity and long-term stability, retaining 73.4% of its response even under high-humidity conditions of 90% RH. DFT calculations indicate that the enhanced sensing performance originates from the RhCu alloy, which shifts the W d-band center from −0.0069 to −0.28188 eV through interfacial electron transfer, thereby optimizing the adsorption strength and charge-transfer efficiency for DMC. Finally, by integrating a microcontroller with a Bluetooth module, real-time sensor data were transmitted to a mobile app, enabling the construction of a device that remotely displays DMC gas concentration in real time, offering a new approach for portable and wireless monitoring of lithium-ion battery electrolyte leakage.