PVDF-HFP/PC基室温高压固态电解质

Room-temperature high-voltage PVDF-HFP/PC-based solid electrolyte

含有强力氢键的聚偏二氟乙烯-co-六氟丙烯(PVDF-HFP)具有优良的抗氧化能力,将其作为电解质基体能够匹配更高电压的阴极材料,有望获得更高的电池能量密度。但基体较高的结晶度严重限制了电解质性能的发挥。通过碳酸丙烯酯(PC)的增塑,降低了体系结晶度,获得了适用于室温高压锂电体系的PVDF-HFP/PC基固态电解质膜,其室温离子电导率达到2.3×10^(-3) S/cm,电化学稳定窗口达到4.8 V(vs.Li/Li^(+)),相对于目前研究最为广泛的聚氧化乙烯(PEO)基固态电解质,其拥有显著优势。将其与高压阴极LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)匹配,实现了固态锂电池在高截止电压下的稳定充放电循环。

The poly(vinylidene fluoride-co-hexafluoro propylene)(PVDF-HFP)containing strong hydrogen bonds has excellent antioxidant capacity,and when used as electrolyte matrix to match high-voltage cathode,it can be expected to achieve higher battery energy density.However,the high crystallinity of the matrix severely limits the performance of the electrolyte.PC plasticization was used to reduce the crystallinity of the system,and PVDF-HFP/PC-based solid electrolyte film suitable for high-voltage lithium battery system at room temperature was obtained.Its ionic conductivity at room temperature reaches 2.3×10^(-3) S/cm,and the electrochemical stability window reaches 4.8 V(vs.Li/Li^(+)).It has significant advantages compared with the PEO-based solid electrolyte which is most widely studied at present.It’s matched with the high-voltage cathode LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NCM622)to realize the stable chargedischarge cycle of solid-state lithium batteries at high cut-off voltage.