Synthesis of highly dispersed Nb2O5–graphene heterojunction composites using ethylene diamine tetraacetic acid and boron-functionalized graphene quantum dots for symmetrical flexible supercapacitors with ultrahigh energy density

Nb 2 O 5 is a promising metal oxide electrode material for supercapacitors because of outstanding structural stability and wide electrochemical window, but low inherent conductivity hinders its many applications.