Room temperature fabricated WO_3-X-based hydrogen sensor with ultra-high detection range

Hydrogen is a key early-warning gas released during lithium-ion battery thermal runaway, making compact and reliable H2 sensors highly desirable. In this work, an optimized WO3 sensing film prepared by powder aerosol deposition (PAD) was directly integrated onto a ceramic micro-hotplate platform to fabricate a miniaturized hydrogen sensor. The Pd/PAD-WO3 device exhibited the best performance at 1.6 V, with a response of ∼ 139 toward 2 vol% H2/ air and a response time of ∼ 3s. It also showed stable responses over a wide H2 concentration range of 1020,000 ppm, with good quantitative fitting behavior (R2=0.998). In addition, the sensor demonstrated good cycling stability, excellent selectivity against common interfering gases, and reliable long-term operation over 60 days. These results confirm the feasibility of integrating PAD-WO3 films with ceramic microhotplates and highlight their potential for lithium-ion battery safety monitoring.