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Li+ ion conduction in two aligned liquid crystalline electrolytes consisting of 10 mol% Li+ salt of a pro-mesogenic anion derived from [closo-1-CB11H12]− in non-ionic hosts was investigated. Using electrochemical impedance spectroscopy (EIS), the ionic conductivity in the parallel (σ‖) and perpendicular (σ⊥) directions of the electrolyte samples was determined using two types of cells: an interdigitated gold electrode and a nylon 6-coated ITO cell. The ratio of ionic conductivities σ⊥/σ‖ in the electrolyte with a nona(ethylene oxide) spacer was about 3 in the entire SmA phase, while in the shorter homologue, the ratio monotonically increases from about 0.4 to 2.9. The liquid crystalline behavior of the hosts and the electrolytes was investigated by optical, thermal, and powder XRD methods. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (ZIBs) offer numerous advantages, such as high energy density, enhanced safety, and low cost, making them an ideal choice for energy storage and conversion applications in the “postlithium” era. Hydrogel electrolytes, as the key component of flexible ZIBs, combine the ionic conductivity of traditional water electrolytes with the dimensional stability of solid polymer electrolytes. However, it remains a challenge to design comprehensive and appropriate hydrogel electrolytes to provide flexible ZIBs with good reversibility and versatility. This review discusses the engineering design of hydrogel electrolytes required for flexible ZIBs from the viewpoint of an electrolyte designer. The basic properties of the hydrogel electrolytes, zinc anodes, cathodes and electrolyte stabilization effects are described in detail. Furthermore, we explore the various challenges faced by hydrogel electrolytes and propose corresponding strategies. Finally, the review offers insights into the future development of hydrogel-stabilized ZIBs. [ABSTRACT FROM AUTHOR]

Ionic liquid (IL)-based gels (ionogels) have received considerable attention due to their unique advantages in ionic conductivity and their biphasic liquid–solid phase property. In ionogels, the negligibly volatile ionic liquid is retained in the interconnected 3D pore structure. On the basis of these physical features as well as the chemical properties of well-chosen ILs, there is emerging interest in the anti-bacterial and biocompatibility aspects. In this review, the recent achievements of ionogels for biomedical applications are summarized and discussed. Following a brief introduction of the various types of ILs and their key physicochemical and biological properties, the design strategies and fabrication methods of ionogels are presented by means of different confining networks. These sophisticated ionogels with diverse functions, aimed at biomedical applications, are further classified into several active domains, including wearable strain sensors, therapeutic delivery systems, wound healing and biochemical detections. Finally, the challenges and possible strategies for the design of future ionogels by integrating materials science with a biological interface are proposed. [ABSTRACT FROM AUTHOR]

The thrust towards a higher energy density and safer alternative to traditional-liquid-electrolyte-based batteries has driven academic and industrial efforts in developing solid-state batteries and particularly solid-state Li/Na–metal batteries (SSLMBs/SSNMBs). Despite research on solid electrolytes seemingly being on a perpetual trajectory, there have been considerable critical issues to be overcome for solid electrolytes, including the insufficient ionic conductivity, low ion-transference number, and poor compatibility with lithium–metal anodes and intercalation cathodes. This feature article sets out efforts to regulate the cubic structure of garnet-type electrolytes, along with a discussion of the solid-solution synthetic approach to produce garnet-type and NASICON (sodium super ion conductor)-type electrolytes, followed by the synthetic strategy for sintering dense nano-grained NASICON-type electrolytes. Next, the mechanochemical synthetic approach and hybrid electrolyte design strategy to mitigate the issues associated with PEO-based composite electrolytes are presented. Finally, the advancement of promising polymeric electrolytes is discussed. We end the perspective with an opinion on the future research in this area. [ABSTRACT FROM AUTHOR]

A thin free-standing composite solid electrolyte film (CSE, ∼15 μm) is prepared by a tape casting and solution infusion method, which owns a high ionic conductivity (2.76 × 10−4 S cm−1 at 25 °C) and a wide electrochemical stability window (4.8 V vs. Li+/Li). The CSE-based solid-state lithium metal batteries with the LiCoO2 cathode present good cycling stability and capacity retention with a 4.5 V cut-off voltage. [ABSTRACT FROM AUTHOR]

Nickel–iron based layered double hydroxide (NILDH) was used for the first time as an inorganic filler to prepare poly(ethylene-oxide)/nickel–iron based layered double hydroxide (PEO/NILDH) composites to improve the properties of PEO-based solid electrolytes. The SEM micrographs and EDS images confirmed the homogeneous dispersion of NILDH particles in the PEO matrix. The XRD and DSC results indicated that the PEO crystallinity tended to decrease with the increase in the amount of NILDH. Meanwhile, the addition of NILDH promoted the improvement of ionic conductivity for PEO/NILDH composites and the maximum value (1.644 × 10−4 S cm−1) appeared at the NILDH concentration of 10 wt%. NILDH with a positive charge surface could increase the lithium-ion transference number by attracting and anchoring the anion of LiTFSI. Meanwhile, the formation of amorphous regions around NILDH was beneficial for the Li+ ion conduction. Furthermore, the electrochemical stability windows of the composite electrolyte were increased to 5.2 V after the addition of NILDH, and the all-solid-state lithium battery using this composite electrolyte showed a specific capacity of 148 mA h g−1 and better cycling performance. The tensile strength of PEO/NILDH composites was enhanced when NILDH was introduced into the PEO matrix with a filler loading of not more than 10 wt%. The remarkable properties of the PEO/NILDH composite make it a potential solid electrolyte material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) emerging as a type of functional material have been widely used in electrochemical energy storage and conversion in recent years. Hollow MOFs with a large pore volume and surface area can increase the contact area between active materials and electrolytes, thus improving the ionic conductivity of the materials. Herein, we obtained a kind of hollow MOF (ZIF-8) using carboxylate-terminated polystyrene microspheres as exterior templates. Transmission electron microscopy and N2 adsorption/desorption analysis revealed that the average cavity diameter of hollow ZIF-8 is 1 μm. Moreover, hollow ZIF-8 exhibits excellent electrochemical quality with an ionic conductivity of 7.36 × 10−4 S cm−1, a lithium ion transference number of 0.83 and an activation energy of 0.15 eV in a wide stable electrochemical window of 2.0–6.5 V at room temperature. Compared with the traditional non-hollow ZIF-8, the electrochemical performance has been improved obviously. Consequently, our strategy of fabrication of large pore volume hollow MOFs provides a new perspective for the development of solid electrolytes with excellent lithium ionic conductivity. [ABSTRACT FROM AUTHOR]