An all-solid-state battery system having a solid-state electrolyte composite is provided. The solid-state electrolyte composite includes a porous framework providing support and mechanical strength for the solid-state electrolyte composite and a plurality of ionic conductors filling voids of the porous framework for maximizing ionic conductance of the solid-state electrolyte composite. The porous framework may be made of ultra-high-molecular-weight polyethylene (UHMWPE) polymers and the plurality of ionic conductors may be made of poly(ethylene oxide)-LiN(SO2CF3)2 (PEO-LiTFSI) polymers. The all-solid-state battery system includes battery cells each including a cathode current collector, a cathode disposed beneath and connected to the cathode current collector, the solid-state electrolyte composite disposed beneath and connected to the cathode, an anode disposed beneath and connected to the solid-state electrolyte composite, and an anode current collector disposed beneath and connected to the anode.