Advancements in power electronics necessitate dielectric polymer films capable of operating at high temperatures and possessing high energy density.Although significant strides have been achieved by integrating inorga...Advancements in power electronics necessitate dielectric polymer films capable of operating at high temperatures and possessing high energy density.Although significant strides have been achieved by integrating inorganic fillers into high-temperature polymer matrices,the inherently low dielectric constants of these matrices have tempered the magnitude of success.In this work,we report an innovative nanocomposite based on sulfonylated polyimide(SPI),distinguished by the incorporation of sulfonyl groups within the SPI backbone and the inclusion of wide bandgap hafnium dioxide(HfO_(2))nanofillers.The nanocomposite has demonstrated notable enhancements in thermal stability,dielectric properties,and capacitive performance at elevated temperatures.Detailed simulations at both molecular and mesoscopic levels have elucidated the mechanisms behind these improvements,which could be attributed to confined segmental motion,an optimized electronic band structure,and a diminished incidence of dielectric breakdown ascribed to the presence of sulfonyl groups.Remarkably,the SPI-HfO_(2)nanocomposite demonstrates a high charge-discharge efficiency of 95.7%at an elevated temperature of 150℃and an applied electric field of 200 MV/m.Furthermore,it achieves a maximum discharged energy density of 2.71 J/cm^(3),signalling its substantial potential for energy storage applications under extreme conditions.展开更多
Dielectric polymers are the materials of choice for high energy density film capacitors.The increasing demand for advanced electrical systems requires dielectric polymers to operate efficiently under extreme condition...Dielectric polymers are the materials of choice for high energy density film capacitors.The increasing demand for advanced electrical systems requires dielectric polymers to operate efficiently under extreme conditions,especially at elevated temperatures.However,the low permittivity and relatively low operating temperature of dielectric polymers limit the high-temperature capacitive energy storage applications.Fortunately,dipolar glass polymers are demonstrated as the preferred materials to achieve high dielectric constant,low dielectric loss and high energy density at elevated temperatures.In this review,we critically elaborate on the recent progress of dipolar glass polymers based on orientational polarization from molecular engineering.In addition,the general design considerations and various dipole moment entities of dipolar glass polymers are described in detail.High dipolar moment,high dipole density and rotation freedom of dipoles are essential for dipolar glass polymers to gain superior dielectric and energy storage properties.Challenges and future opportunities for dipolar glass polymers towards high-temperature energy storage applications are also provided.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52107232,52377026 and 52301192)China Postdoctoral Science Foundation(No.2021M702563)+2 种基金State Key Laboratory of Electrical Insulation and Power Equipment(No.EIPE22312)Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)and Fundamental Research Funds for the Central Universities(No.xzy012024004).
文摘Advancements in power electronics necessitate dielectric polymer films capable of operating at high temperatures and possessing high energy density.Although significant strides have been achieved by integrating inorganic fillers into high-temperature polymer matrices,the inherently low dielectric constants of these matrices have tempered the magnitude of success.In this work,we report an innovative nanocomposite based on sulfonylated polyimide(SPI),distinguished by the incorporation of sulfonyl groups within the SPI backbone and the inclusion of wide bandgap hafnium dioxide(HfO_(2))nanofillers.The nanocomposite has demonstrated notable enhancements in thermal stability,dielectric properties,and capacitive performance at elevated temperatures.Detailed simulations at both molecular and mesoscopic levels have elucidated the mechanisms behind these improvements,which could be attributed to confined segmental motion,an optimized electronic band structure,and a diminished incidence of dielectric breakdown ascribed to the presence of sulfonyl groups.Remarkably,the SPI-HfO_(2)nanocomposite demonstrates a high charge-discharge efficiency of 95.7%at an elevated temperature of 150℃and an applied electric field of 200 MV/m.Furthermore,it achieves a maximum discharged energy density of 2.71 J/cm^(3),signalling its substantial potential for energy storage applications under extreme conditions.
基金financially supported by the National Natural Science Foundation of China(Nos.51973080,92066104 and 51903100)。
文摘Dielectric polymers are the materials of choice for high energy density film capacitors.The increasing demand for advanced electrical systems requires dielectric polymers to operate efficiently under extreme conditions,especially at elevated temperatures.However,the low permittivity and relatively low operating temperature of dielectric polymers limit the high-temperature capacitive energy storage applications.Fortunately,dipolar glass polymers are demonstrated as the preferred materials to achieve high dielectric constant,low dielectric loss and high energy density at elevated temperatures.In this review,we critically elaborate on the recent progress of dipolar glass polymers based on orientational polarization from molecular engineering.In addition,the general design considerations and various dipole moment entities of dipolar glass polymers are described in detail.High dipolar moment,high dipole density and rotation freedom of dipoles are essential for dipolar glass polymers to gain superior dielectric and energy storage properties.Challenges and future opportunities for dipolar glass polymers towards high-temperature energy storage applications are also provided.
