Cyriac Vipin, Mishra Kuldeep, Rao Ankitha, Khellouf Riyadh Abdekadir, Masti Saraswati P, Noor I M
Department of Physics, Manipal Institute of Technology, Manipal Academy of Higher Education Manipal 576104 Karnataka India
Symbiosis Institute of Technology (SIT), Symbiosis International (Deemed University) (SIU) Pune 412115 Maharashtra India.
RSC Adv. 2025 Jul 11;15(30):24350-24366. doi: 10.1039/d5ra02897c. eCollection 2025 Jul 10.
A free-standing, flexible and biodegradable biopolymer electrolyte (BPE) derived from a poly(vinyl alcohol) (PVA)-chitosan (CS) blend immobilizing sodium hexafluorophosphate (NaPF) salt was fabricated solution casting method. The effect of salt concentration on the structural, electrical, and electrochemical properties of the electrolyte was systematically investigated. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy were used to ascertain the microstructural changes in the polymer matrix including the complexation of PVA, CS, and NaPF. Electrochemical impedance spectroscopy (EIS) measurements revealed that the BPE containing 40 wt% NaPF exhibited the highest conductivity (6.94 ± 0.04) × 10 S cm, which was three-order enhancement over the pristine system. The ion transport behaviour, interpreted through the Schütt and Gerdes (S-G) model, revealed that the ionic conductivity of the SPE system is strongly influenced by both the concentration of charge carriers and their mobility. The electrolyte displayed a predominant ionic nature with an electrochemical stability window of ∼3.25 V. When incorporated into an Na-ion EDLC, the optimized electrolyte sample provided a specific capacitance of 42.65 F g, energy density of 5.4 W h kg, and power density of 95 W kg, as determined by galvanostatic charge-discharge (GCD) tests performed at 0.05 mA g.
通过溶液浇铸法制备了一种由固定六氟磷酸钠（NaPF）盐的聚乙烯醇（PVA）-壳聚糖（CS）共混物衍生而来的独立、柔性且可生物降解的生物聚合物电解质（BPE）。系统研究了盐浓度对电解质结构、电学和电化学性能的影响。利用X射线衍射（XRD）和傅里叶变换红外（FTIR）光谱确定聚合物基体中的微观结构变化，包括PVA、CS和NaPF的络合情况。电化学阻抗谱（EIS）测量结果表明，含有40 wt% NaPF的BPE表现出最高电导率（6.94±0.04）×10 S cm，相较于原始体系提高了三个数量级。通过舒特和格德斯（S-G）模型解释的离子传输行为表明，固态聚合物电解质（SPE）体系的离子电导率受电荷载流子浓度及其迁移率的强烈影响。该电解质呈现出主要的离子特性，电化学稳定窗口约为3.25 V。当将其用于钠离子双电层电容器（EDLC）时，通过在0.05 mA g下进行的恒电流充放电（GCD）测试确定，优化后的电解质样品提供了42.65 F g的比电容、5.4 W h kg的能量密度和95 W kg的功率密度。
