Thermally Conductive Nitride-Based Ceramic-Coated-Separator for Lithium-Ion Batteries

As the demand for electric vehicles (EVs) increases, a lot of research to achieve high-energy-density lithium-ion batteries (LIBs) is being actively conducted. However, charging an EV, which takes longer than refueling an internal combustion engine vehicle (ICEVs), is still a common concern. As a way to address this problem, high-rate charging can lead to heat accumulation inside LIBs. In particular, in the case of polyolefin-based separators such as polyethylene and polypropylene, which are currently widely used in LIBs, their low melting temperature threatens the safety of cells during fast charging. To compensate for the low thermal stability of these polyolefin-based separators, ceramic-coated separators (CCS), in which a ceramic coating layer is introduced on the surface of the separator, have now become an essential component for securing the safety of LIBs. Nevertheless, conventional oxide- or hydroxide-based ceramic materials such as Al 2 O 3 , Mg(OH) 2 , AlOOH, etc. still have low thermal conductivity to suppress the heat accumulation especially in large-scale LIBs. Thus, CCSs were fabricated using a nitride-based ceramic material having excellent thermal conductivity. After the CCS was prepared, air permeability, ionic conductivity, thermal stability, and adhesion properties of the ceramic coating layer were measured to be compared with those of Al 2 O 3 -based CCSs. In addition, the thermal conductivity of nitride- and oxide-based CCSs are compared to confirm the possibility to improve the heat dissipation characteristics of the LIBs.