2D MoS2 Nanosheet‐Based Polyimide Nanocomposite with High Energy Density for High Temperature Capacitor Applications

With the development of electrical vehicles and power electronics, the demand for high‐temperature energy storage capacitors with high energy density has grown rapidly. In this investigation, 2D MoS2 nanosheets are coated with a thin layer of poly(methyl methacrylate) and then mixed with polyimide (PI) solution to fabricate nanocomposites. The dielectric constant of MoS2‐g‐PMMA/PI (MPP‐3%) reaches 4.2, which is 20% higher than that of a pristine PI film. The energy density of the MPP‐3% nanocomposite reaches 8.6 J cm−3, which is 40% higher than the highest energy density of a pristine PI film. In addition, the electric breakdown field of the MPP‐3% composite is 50% higher than that of the MoS2/PI nanocomposite without a surface coating. Furthermore, it is found that the highest energy density of MoS2‐g‐PMMA/PI reaches 3.92 J cm−3, which is 47.9% higher than that of the PI film at 150 °C. The charge–discharge efficiency of the nanocomposite film reaches 61.7% at 150 °C. This result is much higher than the previously reported research results for high‐temperature capacitor applications. The MoS2‐g‐PMMA/PI‐based nanocomposite shows great promise for use in high‐temperature capacitor applications. Here, a MoS2‐g‐PMMA/PI (MPP, PI is polyimide) nanocomposite consisting of a thin layer of poly(methyl methacrylate) coated 2D MoS2 nanosheets and PI is reported. The energy density of MPP‐3% nanocomposite (3% MoS2) reaches 8.6 J cm−3. Furthermore, the highest energy density of MoS2‐g‐PMMA/PI reaches 3.92 J cm−3 at 150 °C, which is 47.9% higher than that of the PI film.