Segmental and interfacial dynamics quantitatively determine ion transport in solid polymer composite electrolytes

Abstract

Solid polymer-ceramic composite electrolytes (PCEs) have attracted vast attention for developing solid-state batteries. However, slow ion transport at ambient temperature impedes unlocking their potential. Improving ionic conductivity of PCEs remains a major challenge, because ion transport mechanism in complicated composites is not currently available. This article, for the first time, demonstrates that segmental motion and interfacial polarization are directly coupled, both quantitatively determine ion transport in PCEs. Adding small-molecule additives enhances ionic conductivity in PCEs, by increasing concentration of ions participating in transport and by equally accelerating segmental motion and interfacial dynamics.Accordingly, an ionic conductivity achieves 1.3 Â 10 À3 S/cm at 30 C, simultaneously with high mechanical strength and toughness (solid and flexible, shear modulus G' > 1 MPa). The results may shed a light for better analysis and improved design of solid composite electrolytes, toward meeting material demands for next-generation electrochemical energy storage.

Improving Ion Conductivity in Polymer Blend Electrolytes by Tuning Microdynamics and Interfaces

“…For polymer−ceramic composites, we have recently shown that segmental motion and interfacial polarization both quantitatively determine ion conduction. 28 Quantitative correlations between microdynamics and ionic conductivities have been verified in the polymer blends herein, indicating the universal mechanism for enhancing the ionic conductivity of SPEs. Therefore, our results provide a basis for a better design of polymer electrolytes and unveil the potential for polymer blends to develop qualified SPEs for solid-state batteries.…”

“…Our previous results have suggested that microdynamics quantitatively determine ion conduction in polymer–ceramic composites . To evaluate the correlation in polymer blends, electrochemical impedance measurements are conducted.…”

Ion transport in composite polymer electrolytes

“…Compared with the complex of the polymer matrix and lithium salts, active fillers are lithium-rich, and the state of lithium ions in the interfacial regions is greatly different from those existing in the bulk of the polymer matrix and the active fillers. 78 These differences obviously affect the conduction patterns of lithium ions, and some recent research studies provide conclusive evidence to confirm this.…”

Practical challenges and future perspectives of solid polymer electrolytes: microscopic structure and interface design

“…65,66 This ion hopping process is accompanied by relaxation and segmental motion of the polymer chains, enabling the ions to move along the chains and eventually jump from one polymer chain to another. [67][68][69] Drawing on the transport mechanism observed in inorganic solid electrolytes, the ion hopping in the crystalline regions of a polymer can be described using the Arrhenius equation: 62…”

“…65,66 This ion hopping process is accompanied by relaxation and segmental motion of the polymer chains, enabling the ions to move along the chains and eventually jump from one polymer chain to another. 67–69 Drawing on the transport mechanism observed in inorganic solid electrolytes, the ion hopping in the crystalline regions of a polymer can be described using the Arrhenius equation: 62 In eqn (3), σ 0 represents the ion conductivity, k is Boltzmann's constant, T denotes the operating temperature and E a is the apparent activation energy. As evident from eqn (3), increasing the operating temperature and decreasing the activation energy both contribute to a significant increase in the crystalline region's ion conductivity.…”