Safety assessment of Mn-based lithium-ion battery: thermal stability and vent gas explosion characteristics

Abstract Driven by the goals of carbon neutrality, electrochemical storage technologies play a vital role in supporting the integration of renewable energy and reducing dependency on fossil fuels. The Mn-based rechargeable battery (MnRB) is gaining significant attention in the battery industry due to its high voltage platform and high energy density, making it a potential alternative in the e-bike and energy storage system area. The safety performance of MnRB is crucial for its widespread application. However, there has been a scarcity of studies evaluating the safety of MnRB. In this study, the thermal safety behavior of a commercial Mn-based composite cathode battery from the perspectives of "heat generation-gas emission- explosion risks". Its safety performance was compared with that of existing batteries using Li(Ni x Co y Mn z )O 2 and LiFePO 4 (LFP) as cathode materials. The results indicate that MnRB exhibits a higher triggering temperature, 0.8% lower than Li(Ni 0.5 Co 0.2 Mn 0.3 )O 2 (NCM523) and approximately 12.7% lower than LFP. MnRB's normalized gas emission during thermal runway (TR) is 1.3% lower than that of NCM523, with the primary gas components being CO, H 2 , and CO 2 . The lower explosion limit of MnRB is approximately 2.7% lower than NCM523 and 44.0% higher than LFP. MnRB exhibits intermediate thermal stability and combustion-explosion characteristics between NCM523 and LFP. This study provides valuable data on MnRB's TR behavior, offering a comprehensive assessment of MnRB's intrinsic safety performance through quantitative evaluation. The findings present clear directions for designing, optimizing, and implementing safety measures for MnRB against TR.