Structure, thermal stability and electrical properties of c ellulose‐6‐phosphate : development of a novel fast Na‐ionic conductor

In this study, alkali cellulose‐6‐phosphate (A‐CP) was prepared by the treatment of cellulose‐6‐phosphate (CP) with an aqueous solution of sodium hydroxide. X‐ray diffraction and Fourier transform infrared, 13 C NMR, 31 P NMR and 23 Na NMR spectroscopies were used to characterize the studied polymers. CP and A‐CP crystallize in the monoclinic system of the P 21 space group (cellulose I β ). CP and A‐CP, with relative densities of 70% and 77%, respectively, were shaped into cylindrical pellets by uniaxial pressing and sintering at 423 K of A‐CP. Electrical conductivity measurements of CP and A‐CP were carried out using complex impedance spectroscopy between 298 and 433 K in the frequency range 5 Hz to 13 MHz. The influence of aqueous NaOH on the structure, thermal stability and electrical conductivity of cellulose phosphate was observed. In contrast to CP, A‐CP was stable up to temperatures exceeding 433 K and showed fast ionic conductivity σ 393K  = 2.03 × 10 −6  S cm −1 with an activation energy of 0.73 eV. © 2021 Society of Chemical Industry