Solid polymer electrolyte compositions and methods of preparing same

A solid polymer electrolyte precursor composition, comprising:

• one or more organic solvents;
• one or more cellulosic polymers dissolved in the one or more organic solvents, wherein the one or more cellulosic polymers comprise one or more of cellulose ester, cellulose acetate, and cellulose acetate propionate;
• one or more polymerizable components dissolved or dispersed in the one or more organic solvents;
• one or more photo-initiators dissolved or dispersed in the one or more organic solvents, wherein at least one of the one or more photo-initiators, following irradiation with light, promotes polymerization of at least one of the one or more polymerizable components;
• one or more lithium ion sources dissolved or dispersed in the one or more organic solvents, each lithium ion source comprising a lithium ion salt or a lithium ion complex;
• one or more plasticizers dissolved or dispersed in the one or more organic solvents, wherein a percentage by mass of the one or more plasticizers in the solid polymer electrolyte precursor composition is in a range from one to ten percent;
• and
• one or more ceramic particles dissolved or dispersed in the one or more organic solvents, wherein the one or more ceramic particles comprise nanoparticles of one or more of a titanium oxide, an aluminum oxide, a silicon oxide, a zirconium oxide, a tin oxide, a tungsten oxide, and a tantalum oxide.