Solid　polymer　electrolytes　have　been　considered　as　the　promising　candidates　to　improve　the　safety　and　stability　of　high-energy　lithium　metal　batteries.　However,　the　practical　applications　of　solid　polymer　electrolytes　are　still　limited　by　the　low　ionic　conductivity,　poor　interfacial　contact　with　electrodes,　narrow　electrochemical　window　and　weak　mechanical　strength.　Here,　a　series　of　novel　block　copolymer　electrolytes　with　three-dimensional　networks　are　designed　by　cross-linked　copolymerization　of　the　polyethylene　glycol　soft　segments　and　hexamethylene　diisocyanate　trimer　hard　segments.　Their　ionic　migration　performances　and　interface　compatibilities　with　Li　metal　anode　have　been　optimized　delicately　by　tailoring　the　ratio　of　these　functional　units.　The　optimized　block　copolymer　electrolyte　has　shown　an　amorphous　crystalline　structure,　a　high　ionic　conductivity　of　~5.7　×　10−4　S　cm−1,　high　lithium　ion　transference　number　(~0.49),　wide　electrochemical　window　up　to　~4.65　V　(vs.　Li+/Li)　and　favorable　mechanical　strength　at　55　°C.　Furthermore,　the　enhanced　interface　compatibility　can　well　support　the　normal　operations　of　lithium　metal　batteries　using　both　LiFePO4　and　LiNi0.8Co0.15Al0.05O2　cathodes.　This　study　not　only　paves　a　new　way　to　develop　solid　polymer　electrolyte　with　optimizing　functional　units,　but　also　provides　a　polymer　electrolyte　design　strategy　for　the　application　demand　of　lithium　metal　battery.　©　2020　Science　Press