Solid polymer electrolytes are recently investigated as alternatives to enhance the efficiency of lithium-ion batteries because of their inherent advantages. However, ionic transport through solid polymer electrolytes and mechanical properties of the electrolyte tend to be poorer compared with the liquid organic salt electrolytes. Granted, nanobased materials have attracted increased interest due to their ability to improve the properties of the electrolytes of lithium-ion batteries. This review is intended to highlight recent advances in utilizing nanomaterials in improving the electrochemical and mechanical characteristics of the solid electrolyte to enhance the performance of lithium-ion batteries. The synthetic techniques employed, as well as limitations of nanomaterials, are summarized. Recommendations for further development of novel functional nanomaterials for lithium-ion batteries are presented. Insight from this research will guide researchers in lithium battery technologies to make informed decisions, specifically when using nanobased materials.