Solid biopolymer electrolytes (SBEs) based on 2hydroxyethyl cellulose (2HEC) complexes with dodecyltrimethyl ammonium bromide (DTAB) salt in various composition (wt. %) were successfully prepared by using solution casting technique. The ion – polymer interaction and structural studies have been reported by Fourier transform infrared spectroscopy (FTIR) supported with X – ray diffraction (XRD) and Electrical impedance spectroscopy (EIS). FTIR spectral shows interaction of 2HEC with DTAB happen at peak 2914cm−1, 2848cm−1, 2353cm−1, 2328cm−1, 1720cm−1, 1437cm−1, 1344cm−1, 1198cm−1 1095cm−1 1051cm−1, 912cm−1 and 872cm−1. The interaction of complexes leads to an increase in number of ion jump into neighboring vacant sites until it reaches the highest conductivity at room temperature which is 2.80 x 10−5 Scm−1 for sample containing 9wt. % of DTAB. The temperature dependence of the SBEs system exhibits Arrhenius behavior and the XRD spectral analysis shows the higher salt loading the crystallinity of the SBEs which also increased.