Importance of Thermal Transport for the Design of Solid-State Battery Materials

Battery technologies have evolved rapidly over the past decade, including the advent of solid-state batteries. In this time, it has become apparent that thermal management is paramount for device operation and lifetime. However, the fundamental importance of the thermal properties of materials, such as thermal conductivity, in engineering design and mitigating the risk of catastrophic failure is yet to be fully understood. This Perspective aims to provide motivation for the fields of thermal transport and ionic transport to join forces to understand heat transport for better battery design, especially in light of solid-state batteries. From the basic characterization of thermal conductivity in bulk materials to considering the full complexity of battery composites during electrochemical cycling, there are many potential directions for fundamental and applied investigations. We anticipate that studying heat transport in battery materials has the added benefit of extending the design space to other functional devices. The difficulty in controlling heat transport in solid-state energy devices, including microelectronics, batteries, and thermoelectrics, is often a limiting factor in improving device performance. Especially in batteries, not only can excessive heat cause degradation that leads to a loss of charge capacity over time, but thermal runaway can occur when the battery overheats to catastrophic failure. Thus, understanding heat evolution and thermal transport in batteries is an important step to improve lifetime and safety. It is from this perspective that we provide the motivation for the importance of bringing together the fields of thermal transport and battery research, particularly to study solid-state batteries, which epitomize the overall complexity of battery systems and require a state-of-the-art understanding of thermal transport mechanisms. Here, we identify the basic and applied scientific directions that may prove fruitful for the next generation of battery thermal management.