Composite electrodes are disclosed that comprise an active electrode material and a solid electrolyte, wherein the solid electrolyte is a composite electrolyte. The composite electrolyte comprises an electrically insulating material having a plurality of pores and a solid electrolyte material covering inner surfaces of the plurality of pores. The active electrode material may comprise a plurality of active electrode material particles in electrical contact with each other, and the composite electrolyte may be located in spaces between the plurality of active electrode material particles. The present disclosure is further related to solid-state batteries comprising a stack of an anode, a solid electrolyte layer, and a cathode, wherein at least one of the anode and the cathode is a composite electrode according to the present disclosure. The present disclosure further provides methods for fabricating such composite electrodes and solid-state batteries.