Wang Bingbing, Lou Hongming, Xu Hongli, Zhao Junpeng, Wang Qiujun, Shi Qiao, Deng Yonghong
School of Chemistry and Chemical Engineering, South China University of Technology Guangzhou 516640 China
Department of Materials Science and Engineering, South University of Science and Technology of China Shenzhen 518055 China
RSC Adv. 2018 Feb 8;8(12):6373-6380. doi: 10.1039/c7ra13664a. eCollection 2018 Feb 6.
In this work, a novel star-comb copolymer based on poly(d,l-lactide) (PDLLA) macromonomer and poly(ethylene glycol)methyl ether methacrylate (PEGMA) was prepared, and the electrochemical properties were studied, with the aim of using it as a solid polymer electrolyte in lithium ion batteries. The six-arm vinyl functionalized PDLLA macromonomer was synthesized by a ring-opening polymerization (ROP) of d,l-lactide and subsequently an acylation of the hydroxy end-groups. A series of free-standing solid polymer electrolyte membranes from different ratios of PDLLA, PEGMA and LiTFSI were prepared through solvent-free free radical polymerization under UV radiation. The chemical structure of the obtained polymers was confirmed by H NMR and FTIR. The as-prepared six-arm star-comb solid polymer electrolytes (PDLLA-SPEs) exhibit good thermal stability with s of ∼270 °C and low s of -48 to -34 °C. The electrochemical characterization shows that the PDLLA-SPEs possess a wide electrochemical window up to 5.1 V with an optimal ionic conductivity of 9.7 × 10 S cm at 60 °C at an EO/Li ratio of 16 : 1. Furthermore, the all-solid-state LiFePO/Li cells display extraordinary cycling and rate performances at 60 °C by curing the PDLLA-SPEs directly on the cathode. These superior properties of the six-arm star-comb PDLLA-SPE make it a promising candidate solid electrolyte for lithium batteries.
在本工作中，制备了一种基于聚（d，l-丙交酯）（PDLLA）大分子单体和聚（乙二醇）甲基醚甲基丙烯酸酯（PEGMA）的新型星型梳状共聚物，并对其电化学性能进行了研究，旨在将其用作锂离子电池的固体聚合物电解质。通过d，l-丙交酯的开环聚合（ROP），随后对羟基端基进行酰化反应，合成了六臂乙烯基官能化的PDLLA大分子单体。通过在紫外辐射下的无溶剂自由基聚合，制备了一系列由不同比例的PDLLA、PEGMA和LiTFSI组成的自支撑固体聚合物电解质膜。通过1H NMR和FTIR确认了所得聚合物的化学结构。所制备的六臂星型梳状固体聚合物电解质（PDLLA-SPEs）表现出良好的热稳定性，玻璃化转变温度约为270°C，低熔点在-48至-34°C之间。电化学表征表明，PDLLA-SPEs具有高达5.1 V的宽电化学窗口，在60°C、EO/Li比为16∶1时，最佳离子电导率为9.7×10-6 S cm-1。此外，通过将PDLLA-SPEs直接固化在阴极上，全固态LiFePO4/Li电池在60°C下表现出优异的循环和倍率性能。六臂星型梳状PDLLA-SPEs的这些优异性能使其成为锂电池中一种有前途的候选固体电解质。
