Solid polymer electrolytes (SPEs) present substantial potential for use in solid-state lithium batteries; however, their authentic usability is presently curbed by their inadequate ionic conductivity and restricted lithium-ion mobility. Herein, a strategy to enhance the performance of poly(vinylidene fluoride) (PVDF) composite polymer electrolytes (CPEs) using two-dimensional cobalt-based ultrathin metal-organic framework nanosheet (CMS) with a high aspect ratio is proposed. At a CMS loading of 8 wt%, the obtained CPEs displayed a high ionic conductivity of 6.26 x 10-4 S cm-1 (28 degrees C). I...