An emulsion, an emulsion gel electrolyte, an aerogel, as well as a preparation method and a use; wherein the emulsion is an oil-in-water emulsion. An oil phase is a solution of decane dispersed with an upconversion nanomaterial and a water phase contains a polymerizable ionic liquid. The gel electrolytes and aerogel electrode materials prepared based on this emulsion have greatly improved the electrochemical performance of supercapacitors.