Polymer dielectric is the essential component of film capacitor. High performance dielectric material

which is able to withstand the harsh conditions of electrothermal coupling

is key to improve the energy storage and energy conversion characteristics of film capacitor. The current commercial polymer films fail to meet the requirements of high temperature and high electric field simultaneously. In this research

a strategy for polymer development based on rational design of molecular structure is reviewed. Based on the experiments

theoretical calculations and mechanism analysis of a large number of polymer properties

the key design indexes and the molecular structure features of polymer resistant to high temperature and strong electric field are proposed. A novel molecular structure of polynorbornene is designed and actually synthesized

the withstand ability of which to the harsh conditions of electrothermal coupling is excellent. The modification of end groups and main chains in molecular structure can achieve the enhancement of energy storage density. Therefore

the new research approach of high performance dielectric materials based on molecular structure design has got rid of the traditional model by trial-verification

and put forward a new paradigm of dielectric materials research under multi-objective constraints.