Chemically bonding inorganic fillers with polymer to achieve ultra-stable solid-state sodium batteries

• Published in: Journal of colloid and interface science Vol. 648; pp. 855 - 864
• Main Authors: Yin, Xuemin, Feng, Wuliang, Cheng, Shuling, Huang, Qiuan, Zou, Xingli, Wang, Zhenwei, Yang, Xinxin, Lu, Shigang, Lu, Xionggang, Zhao, Yufeng
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.10.2023
• Subjects: Composite solid electrolytes; Interfacial compatibility; Solid-state sodium batteries; Ultra-stable performance; Interfacial compatibility; Solid-state sodium batteries; Composite solid electrolytes; Ultra-stable performance
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.06.064

A homogeneous I-PEO-SiO2 electrolyte was successfully prepared via an in-situ synthesis of SiO2 particles in PEO. The SiO2 particles and PEO chains are closely welded by strong chemical bonds, leading to the uniform distributed SiO2 in PEO, which effectively resolved the issue of inorganic/organic interface and realized excellent dendrite-suppression. Consequently, the I-PEO-SiO2 electrolyte exhibited a high ionic conductivity and excellent electrochemical stability. [Display omitted] Inorganic/organic composite solid electrolytes (CSEs) have attracted ever-increasing attentions due to their outstanding mechanical stability and processibility. However, the inferior inorganic/organic interface compatibility limits their ionic conductivity and electrochemical stability, which hinders their application in solid-state batteries. Herein, we report a homogeneously distributed inorganic fillers in polymer by in-situ anchoring SiO2 particles in polyethylene oxide (PEO) matrix (I-PEO-SiO2). Compared with ex-situ CSEs (E-PEO-SiO2), SiO2 particles and PEO chains in I-PEO-SiO2 CSEs are closely welded by strong chemical bonds, thus addressing the issue of interfacial compatibility and realizing excellent dendrite-suppression ability. In addition, the Lewis acid-base interactions between SiO2 and salts facilitate the dissociation of sodium salts and increase the concentration of free Na+. Consequently, the I-PEO-SiO2 electrolyte demonstrates an improved Na+ conductivity (2.3 × 10−4 S cm−1 at 60 °C) and Na+ transference number (0.46). The as constructed Na3V2(PO4)3 ‖ I-PEO-SiO2 ‖ Na full-cell demonstrates a high specific capacity of 90.5 mAh g−1 at 3C and an ultra-long cycling stability (>4000 cycles at 1C), outperforming the state-of-the-art literatures. This work provides an effective way to solve the issue of interfacial compatibility, which can enlighten other CSEs to overcome their interior compatibility.