Rugh Haley J, Lee Jaeyong, Sun Chenyue, Abdo Emily E, Bem Juliana N, Balsara Nitash P, Coates Geoffrey W
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853-1301, USA.
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California, 94720-1462, USA.
Angew Chem Int Ed Engl. 2025 Jan 10;64(2):e202415069. doi: 10.1002/anie.202415069. Epub 2024 Nov 22.
Polymer electrolytes exhibit higher energy density and improved safety in lithium-ion batteries relative to traditionally used liquid electrolytes but are currently limited by their lower electrochemical performance. Aiming to access polymer electrolytes with competitive electrochemical properties, we developed the anionic ring-opening polymerization (AROP) of cyclic silaketals to synthesize amorphous silicon-containing polyether-based electrolytes with varying substituent bulk of the general formula [OSi(R)(CHCHO)] (R=alkyl, phenyl). As opposed to previously reported uncontrolled polycondensation routes toward low molecular weight polysilaketals, AROP allows access to targeted molecular weights above the entanglement threshold of the polymers. The polysilaketal with the lowest steric bulk (P(OSi-2EO)) exceeds the conductivity of poly(ethylene oxide) (PEO), a leading polymer electrolyte. To the best of our knowledge, this is the first solid polymer electrolyte to achieve this benchmark. Steric bulk in polysilaketals was found to impart stability and two bulkier polysilaketals, P(OSi-2EO) and P(OSi-2EO), exhibited higher current fractions than PEO over a wide range of salt loadings. Moreover, the efficacy of P(OSi-2EO) was competitive with that of PEO. Taken together, the tunable and competitive electrochemical properties of polysilaketals validate the systematic incorporation of silyl groups as a strategy to access high performance polymer electrolytes.
相对于传统使用的液体电解质，聚合物电解质在锂离子电池中表现出更高的能量密度和更好的安全性，但目前其较低的电化学性能限制了它们的应用。为了获得具有竞争力电化学性能的聚合物电解质，我们开发了环状硅酮缩醛的阴离子开环聚合（AROP）方法，以合成具有不同取代基体积的通式为[OSi(R)(CHCHO)]（R = 烷基、苯基）的含无定形硅聚醚基电解质。与先前报道的生成低分子量聚硅酮缩醛的无控制缩聚路线不同，AROP能够获得高于聚合物缠结阈值的目标分子量。空间位阻最小的聚硅酮缩醛（P(OSi-2EO)）超过了领先的聚合物电解质聚环氧乙烷（PEO）的电导率。据我们所知，这是第一种达到这一基准的固体聚合物电解质。发现聚硅酮缩醛中的空间位阻赋予了稳定性，并且在广泛的盐负载范围内，两种空间位阻更大的聚硅酮缩醛P(OSi-2-2EO)和P(OSi-2-4EO)比PEO表现出更高的电流分数。此外，P(OSi-2-2EO)的效能与PEO相当。综上所述，聚硅酮缩醛可调节且具有竞争力的电化学性能验证了将硅烷基团系统地引入作为获得高性能聚合物电解质的一种策略。
