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Crosslinked Poly(tetrahydrofuran) as a Loosely Coordinating Polymer Electrolyte
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2018-07-15 , DOI: 10.1002/aenm.201800703 David G. Mackanic 1 , Wesley Michaels 1 , Minah Lee 1 , Dawei Feng 1 , Jeffrey Lopez 1 , Jian Qin 1 , Yi Cui 2 , Zhenan Bao 1
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2018-07-15 , DOI: 10.1002/aenm.201800703 David G. Mackanic 1 , Wesley Michaels 1 , Minah Lee 1 , Dawei Feng 1 , Jeffrey Lopez 1 , Jian Qin 1 , Yi Cui 2 , Zhenan Bao 1
Affiliation
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Solid polymer electrolytes (SPEs) promise to improve the safety and performance of lithium ion batteries (LIBs). However, the low ionic conductivity and transference number of conventional poly(ethylene oxide) (PEO)‐based SPEs preclude their widespread implementation. Herein, crosslinked poly(tetrahydrofuran) (xPTHF) is introduced as a promising polymer matrix for “beyond PEO” SPEs. The crosslinking procedure creates thermally stable, mechanically robust membranes for use in LIBs. Molecular dynamics and density functional theory (DFT) simulations accompanied by 7Li NMR measurements show that the lower spatial concentration of oxygen atoms in the xPTHF backbone leads to loosened O–Li+ coordination. This weakened interaction enhances ion transport; xPTHF has a high lithium transference number of 0.53 and higher lithium conductivity than a xPEO SPE of the same length at room temperature. It is demonstrated that organic additives further weaken the O–Li+ interaction, enabling room temperature ionic conductivity of 1.2 × 10−4 S cm−1 with 18 wt% N,N‐dimethylformamide in xPTHF. In a solid‐state LIB application, neat xPTHF SPEs cycle with near theoretical capacity for 100 cycles at 70 °C, with rate capability up to 1 C. The plasticized xPTHF SPEs operate at room temperature while maintaining respectable rate capability and capacity. The novel PTHF system demonstrated here represents an exciting platform for future studies involving SPEs.
中文翻译：
交联聚四氢呋喃作为疏配聚合物电解质
固态聚合物电解质（SPE）有望改善锂离子电池（LIB）的安全性和性能。但是，基于常规聚环氧乙烷（PEO）的SPE的低离子电导率和转移数使其无法广泛实施。在此，引入了交联的聚四氢呋喃（xPTHF）作为“超越PEO” SPE的有前途的聚合物基质。交联过程产生了用于LIB的热稳定，机械坚固的膜。分子动力学和密度泛函理论（DFT）模拟以及7 Li NMR测量表明，xPTHF主链中较低的氧原子空间浓度会导致O–Li +松散协调。这种减弱的相互作用增强了离子的转运；与在室温下相同长度的xPEO SPE相比，xPTHF具有0.53的高锂转移数和更高的锂电导率。结果表明，有机添加剂可进一步弱化O-Li +相互作用，使室温离子电导率为1.2×10 -4 S cm -1且N，N含量为18％xPTHF中的二甲基甲酰胺。在固态LIB应用中，纯xPTHF SPE在70°C时具有接近理论容量的100个循环的循环，速率能力高达1C。增塑的xPTHF SPE在室温下运行，同时保持可观的速率能力和容量。此处展示的新型PTHF系统为涉及SPE的未来研究提供了一个令人兴奋的平台。
更新日期：2018-07-15
中文翻译：
交联聚四氢呋喃作为疏配聚合物电解质
固态聚合物电解质（SPE）有望改善锂离子电池（LIB）的安全性和性能。但是，基于常规聚环氧乙烷（PEO）的SPE的低离子电导率和转移数使其无法广泛实施。在此，引入了交联的聚四氢呋喃（xPTHF）作为“超越PEO” SPE的有前途的聚合物基质。交联过程产生了用于LIB的热稳定，机械坚固的膜。分子动力学和密度泛函理论（DFT）模拟以及7 Li NMR测量表明，xPTHF主链中较低的氧原子空间浓度会导致O–Li +松散协调。这种减弱的相互作用增强了离子的转运；与在室温下相同长度的xPEO SPE相比，xPTHF具有0.53的高锂转移数和更高的锂电导率。结果表明，有机添加剂可进一步弱化O-Li +相互作用，使室温离子电导率为1.2×10 -4 S cm -1且N，N含量为18％xPTHF中的二甲基甲酰胺。在固态LIB应用中，纯xPTHF SPE在70°C时具有接近理论容量的100个循环的循环，速率能力高达1C。增塑的xPTHF SPE在室温下运行，同时保持可观的速率能力和容量。此处展示的新型PTHF系统为涉及SPE的未来研究提供了一个令人兴奋的平台。
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