A positive electrode including an active layer is provided, where the active layer includes a plurality of positive electroactive solid-state particles, a lithium-source material coated on or dispersed with the positive electroactive solid-state particles in the active layer, and a polymeric gel electrolyte at least partially filling voids between the positive electroactive solid-state particles in the active layer. The lithium-source material having a theoretical specific capacity greater than or equal to about 100 mAh/g to less than or equal to about 3,000 mAh/g.