Synergism of lithium acetate salt toward surface chemistry and physical properties of carboxymethyl chitosan‐based solid polymer electrolyte

Abstract Solid polymer electrolyte (SPE) nowadays becomes the key enablers in building structural framework of better electrolytes for all‐solid‐sate lithium‐ion batteries (ASS LIBs). A main question remains how to wisely improve the conductivity of polysaccharides, thus promoting today's transition from fossil fuels to green energy. Herein, development of conductive carboxymethyl chitosan (CMCh) complex involving the synergistic impact of lithium acetate (LiCH 3 COO) is proposed. Changes in the surface chemistry of CMCh appear, suggesting a successful functionalization to this chitosan derivative in the presence of LiCH 3 COO. Following this, SPE containing 20 wt% lithium acetate optimally demonstrates the highest ionic conductivity equivalent to 5.37 × 10 −3 S. cm −1 . However, salt‐added CMCh has a crystallinity index (Cr.I) of 64.57% and a tensile strength of 4.74 MPa, which is lower than the neat CMCh SPE membrane. The success loading of lithium acetate also results in a rougher surface of CMCh membrane than of its reference. Further, salt‐incorporated CMCh membrane exhibits a reduction in the thermal stability. In addition, eventually, these presented findings underpin potential application of this chitosan derivative for future ASS LIBs.