Hierarchically structured metal carbides as conductive fillers in thermo-responsive polymer nanocomposites for battery safety

Integrating thermo-responsive polymer switching materials (TRPS) into lithium-ion batteries (LIBs) has been recognized as one of the most effective strategies to prevent thermal runaway under various abuse scenarios. However, the current methods to obtain TRPS cannot satisfy different practical applications. Herein, we develop a versatile strategy for the preparation of various metal carbides (e.g., tungsten carbide, molybdenum carbide) with controllable hierarchical structure that is featured with surface protrusion structure, which is critical for high conductivity and rapid thermal response. Systematic studies of the phase and morphology evolutions by advanced characterizations illustrate that the reducing agent and reduction rate are critical for developing the specific morphology. By using the above-mentioned carbides as the conductive fillers of TRPS, the resulting TRPS with a specially controlled shape exhibits over 5 order of conductivity improvement compared with common carbides with particulate morphology, in addition to reversible shutdown performance and effective thermal abuse protections toward safe LIB operation.

Automated summary

Integrating thermo-responsive polymer switching materials (TRPS) into lithium-ion batteries (LIBs) is recognized as an effective strategy to prevent thermal runaway. This study develops a versatile strategy to prepare metal carbides with controllable hierarchical structure, which greatly improves the conductivity and thermal response rate of TRPS. The resulting TRPS shows enhanced conductivity, reversible shutdown performance, and effective thermal abuse protection, making it suitable for safe LIB operation.