Polymer-in-salt solid electrolytes for lithium-ion batteries

Solid-state polymer lithium-ion batteries with better safety and higher energy density are one of the most promising batteries, which are expected to power future electric vehicles and smart grids. However, the low ionic conductivity at room temperature of solid polymer electrolytes (SPEs) decelerates the entry of such batteries into the market. Creating polymer-in-salt solid electrolytes (PISSEs) where the lithium salt contents exceed 50[Formula: see text]wt.% is a viable technology to enhance ionic conductivity at room temperature of SPEs, which is also suitable for scalable production. In this review, we first clarify the structure and ionic conductivity mechanism of PISSEs by analyzing the interactions between lithium salt and polymer matrix. Then, the recent advances on polyacrylonitrile (PAN)-based PISSEs and polycarbonate derivative-based PISSEs will be reviewed. Finally, we propose possible directions and opportunities to accelerate the commercializing of PISSEs for solid polymer Li-ion batteries.

Preparation and properties of multilayered polymer/nanodiamond composites via an in situ technique

Compared to conventional materials, nanocomposites of conjugated polymers are found to have excellent performance due to a larger exposed surface area. In this study, polyaniline (PANi), polypyrrole (PPy), polythiophene (PTh) and polyazopyridine (PAP)/nanodiamonds (NDs) composites were efficiently synthesized by in situ oxidative polymerization. Physical characteristics of fabricated nanocomposites were explored using Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). FTIR indicated layer-by-layer oxidative polymerization of various matrices on functional ND (F-ND) surfaces. FESEM revealed the fibrillar (web-like) morphology of multilayered nanocomposites having a granular arrangement of NDs. TGA of multilayered F-NDs/PAP/PANi/PTh showed 10% degradation at an enhanced temperature of 482°C compared with F-NDs/PANi/PPy/PTh (471°C). Improvement in glass transition of layered material was observed from 99°C (NDs/PANi/PPy/PTh) to 121°C (NDs/PAP/PANi/PTh). Functional filler also contributed towards the enhancement in the conductivity of NDs/PAP/PANi/PTh (5.7 S cm-1) relative to NDs/PANi/PPy/PTh (3.7 S cm-1) systems. New conducting composites are potentially important in various applications, including polymer lithium-ion batteries.