Journal Article single-atom catalysts CO2 electroreduction KIBs Li-CO2 batteries active sites atomic cluster catalysts band optimization bimetallic selenides carbon anodes carbon quantum dots charge balance delocalization of spin states efficiency electrocatalysis electrocatalysts electronic synergy exciton quenching heterostructures homojunctions interface engineering light-emitting diodes metal-air batteries nanorods nanosheets orbital interaction potassium-ion batteries quantum dots structure-function relationship sulfur-doped carbons