Upgrading comprehensive performances of gel polymer electrolyte based on polyacrylonitrile via copolymerizing acrylonitrile with N-vinylpryrrolidone

Application of the Supercapacitor for Energy Storage in China: Role and Strategy

Supercapacitors are widely used in China due to their high energy storage efficiency, long cycle life, high power density and low maintenance cost. This review compares the differences of different types of supercapacitors and the developing trend of electrochemical hybrid energy storage technology. It gives an overview of the application status of supercapacitors in China’s smart grid and Energy Internet in detail. Some strategies and constructive suggestions are put forward to solve the existing problems. With the improvement of the grid-connected capacity of new energy power generation during the 14th Five-year Period of China, the supercapacitor market in China will usher in a good development opportunity. The role of the supercapacitor in achieving carbon peak carbon neutralization is prospected.

Preparation of Quaternary Amphiphilic Block Copolymer PMA-b-P (NVP/MAH/St) and Its Application in Surface Modification of Aluminum Nitride Powders

Poly(methyl acrylate)-b-poly(N-vinyl pyrrolidone/maleic anhydride/styrene) (PMA-b-P (NVP/MAH/St)) quaternary amphiphilic block copolymer prepared by reversible addition-fragmentation chain transfer (RAFT) was used to improve the anti-hydrolysis and dispersion properties of aluminum nitride (AIN) powders that were modified by copolymers. Its structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and Hydrogen nuclear magnetic spectroscopy (¹H-NMR). The results demonstrate that the molecular weight distribution of the quaternary amphiphilic block copolymers is 1.35–1.60, which is characteristic of controlled molecular weight and narrow molecular weight distribution. Through charge transfer complexes, NVP/MAH/St produces a regular alternating arrangement structure. After being treated with micro-crosslinking, AlN powder modified by copolymer PMA-b-P(NVP/MAH/St) exhibits outstanding resistance to hydrolysis and can be stabilized in hot water at 50 °C for more than 14 h, and the agglomeration of powder particles was improved remarkably.

Flexible poly(vinylidene fluoride-co-hexafluoropropylene)-based gel polymer electrolyte for high-performance lithium-ion batteries

Gel polymer electrolytes (GPEs) have attracted ever-increasing attention in Li-ion batteries, due to their great thermal stability and excellent electrochemical performance. Here, a flexible poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based GPE doped with an appropriate proportion of the PEO and SiO₂ is developed through a universal immersion precipitation method. This porous PVDF-HFP-PEO-SiO₂ GPE with high ionic conductivity and lithium-ion transference number (t_Li⁺) can enhance the electrochemical performance of LiFePO₄ cells, leading to superior rate capability and excellent cycling stability. Moreover, the PVDF-HFP-PEO-SiO₂ GPE effectively inhibits the lithium dendrite growth, thereby improving the safety of Li-ion batteries. In view of the simplicity in using the gel polymer electrolyte, it is believed that this novel GPE can be used as a potential candidate for high-performance Li-ion batteries.

Gel polymer electrolytes (GPEs) have attracted ever-increasing attention in Li-ion batteries, due to their great thermal stability and excellent electrochemical performance.

Study of a composite solid electrolyte made from a new pyrrolidone-containing polymer and LLZTO

Improving the safety and performance of lithium ion batteries (LIB) sparked the idea of using a solid electrolyte to construct all-solid-state ones. In this study, a composite solid polymer electrolyte based on Li_6.40La₃Zr_1.40Ta_0.60O₁₂ (LLZTO) nanoparticles and a random copolymer, poly(vinyl pyrrolidone-co-poly(oligo(ethylene oxide) methyl ether methacrylate) (PPO), was successfully prepared and investigated in detail. The copolymer PPO is mixed with LiTFSI and LLZTO at different ratios and the Li conductivity and other electrochemical properties were studied. The copolymer matrix shows the highest ionic conductivity, 2.43 × 10^-5 S/cm at 60 °C, at the content of 20 wt% LiTFSI, the highest lithium ion transference number is determined to be 0.33 at room temperature, and the electrochemical stability reaches 4.3 V vs. Li⁺/Li. Interestingly, when compounded with LLZTO nanoparticles, the ionic conductivity is not improved much. For example, the highest ionic conductivity increases a little to 2.74 × 10^-5 S/cm at 60 °C when 5 wt% LLZTO is added. However, a large increase in electrochemical stability to 5.0 V is obtained for the sample of PPO-20%-10LLZTO. Both PPO and the composite electrolyte show good cycling performance during a plating/stripping experiment at a current density of 0.01 mA/cm². The limited improvement of properties is possibly due to the poor interface contact between PPO and LLZTO nanoparticles. The result may shed light on the complexity of fabricating composite electrolytes using mixtures of polymer and lithium-conducting ceramics.