Hybrid Liquid-Crystalline Electrolytes with High-Temperature-Stable Channels for Anhydrous Proton Conduction

Abstract

Modern electrochemical and electronic devices require advanced electrolytes. Liquid crystals have emerged as promising electrolyte candidates due to their good fluidity and long-range order. However, the mesophase of liquid crystals is variable upon heating, which limits their applications as high-temperature electrolytes, e.g., implementing anhydrous proton conduction above 100 °C. Here, we report a highly stable thermotropic liquid-crystalline electrolyte based on the electrostatic self-assembly of polyoxometalate (POM) clusters and zwitterionic polymer ligands. These electrolytes can form a well-ordered mesophase with sub-10 nm POM-based columnar domains, attributed to the dynamic rearrangement of polymer ligands on POM surfaces. Notably, POMs can serve as both electrostatic cross-linkers and high proton conductors, which enable the columnar domains to be high-temperature-stable channels for anhydrous proton conduction. These nanochannels can maintain constant columnar structures in a wide temperature range from 90 to 160 °C. This work demonstrates the unique role of POMs in developing high-performance liquid-crystalline electrolytes, which can provide a new route to design advanced ion transport systems for energy and electronic applications.

The Novel Ionic Liquid and Its Related Self‐Assembly in the Areas of Energy Storage and Conversion

“…Reproduced with permission. [ 98 ] Copyright 2021, American Chemical Society. c) Compositions and procedure for all‐solid‐state electrolyte PILC/PEO preparation within a DSSC.…”

“…[87,100] For instance, Chai et al reported a thermotropic ILC electrolyte by the self-assembly of a polyoxometalate cluster H 4 SiW 12 O 40 (SiW) and an amphiphilic zwitterionterminated polymer ligand (Figure 6b). [98] The zwitterionic consisted of an imidazole ring and a sulfonate group, and created a system with well-defined microphase separation. Moreover, there were strong interactions between SiW anions and the imidazole ring, while the protons of SiW were captured by the sulfonate group.…”

“…b) The Fabrication of Polyoxometalate-Based Liquid-Crystalline Electrolyte SiW-4IPSn and the Formation of Its Columnar Nanophase. Reproduced with permission [98]. Copyright 2021, American Chemical Society.…”

Multifunctional polyzwitterion ionic liquid coating for long-lifespan and dendrite-free Zn metal anodes

“…Zwitterionic salts have been used as polymer electrolytes and additives to improve ionic conductivity. [28][29][30][31] Furthermore, zwitterionic polymers contain a sea of cationic and anionic groups along their backbone, which can provide an ion transmission channel and maintain overall charge neutrality, enabling a uniform distribution of the electric eld at the electrode/electrolyte interface.…”

Developing a Unique Hydrogen-Bond Network in a Uranyl Coordination Framework for Fuel Cell Applications

“…Among the new classes of solid-state electrolytes, crystalline materials, such as coordination polymers (CPs), metal–organic frameworks (MOFs), hydrogen-bonded organic frameworks (HOFs), and covalent organic frameworks (COFs), have attracted scientists and engineers’ attention, as these crystalline materials provide a powerful tool for understanding the pathway and mechanism of proton transportation through atomic-level structural information to control and optimize proton conductivity. − From the perspective of proton-conducting materials, the proton conductivity is mainly determined through the proton pathway, the amount, and mobility of proton carriers. Furthermore, in proton-conducting CPs/MOFs, proton conductivity may be affected by intrinsic factors such as substitution of building blocks (metal clusters, ligands, and guest molecules/ions). − Therefore, the desired proton-conducting behavior of crystalline materials can be controlled through the optimization of these building blocks.…”