Bifunctional flame retardant solid-state electrolyte toward safe Li metal batteries

• Published in: Journal of energy chemistry 2023-06, Vol.81, p.613-622
• Main Authors: Lv, Qiang, Song, Yajie, Wang, Bo, Wang, Shangjie, Wu, Bochen, Jing, Yutong, Ren, Huaizheng, Yang, Shengbo, Wang, Lei, Xiao, Lihui, Wang, Dianlong, Liu, Huakun, Dou, Shixue
• Format: Article
• Language: English
• Subjects: Fireproof property; Hydroxyapatite; Li dendrites; N-methyl pyrrolidone; PVDF-HFP; Safe Li metal batteries; Solid polymer electrolytes
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2023.02.040

A bifunctional flame retardant SPE was designed by combining HAP and NMP additives in PVDF-HFP matrix to achieve safe Li metal batteries with high performance. [Display omitted] Solid polymer electrolytes (SPEs) are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries. Nevertheless, the poor ionic conductivity at room temperature (RT) and low resistance to Li dendrites seriously hinder the commercialization of SPEs. Herein, we design a bifunctional flame retardant SPE by combining hydroxyapatite (HAP) nanomaterials with N-methyl pyrrolidone (NMP) in the PVDF-HFP matrix. The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of LiTFSI in the PVDF-HFP matrix. Consequently, the prepared SPE demonstrates superior ionic conductivity at RT, excellent fireproof properties, and strong resistance to Li dendrites. The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 mA cm−2, and the solid-state LiFePO4||Li cell shows excellent capacity retention of 85.3% over 600 cycles at 0.5 C.