F127/纤维素复合固态电解质的双锂盐调控与电池性能研究

doi:10.16552/j.cnki.issn1001-1625.2025.1208

摘要/Abstract

摘要：

针对聚醚类固态电解质与锂金属负极之间界面稳定性差的问题，本研究采用双锂盐策略，设计并制备了一种F127/纤维素复合固态电解质。通过热熔法将LiTFSI和LiDFOB复配的双盐体系与F127共混，制备均匀的聚合物浆料，并将其灌入纤维素多孔膜中，获得结构致密的复合电解质。研究表明，LiDFOB的引入能显著改善电解质/锂金属界面性能，促进形成稳定的固体电解质界面（SEI）层。电化学测试结果表明，双盐电解质在60 ℃下的离子电导率达2.0×10^-4 S·cm^-1，锂离子迁移数提升至0.31。基于该电解质组装的Li/Li对称电池极限电流密度提高至0.5 mA·cm^-2，在 0.1 mA·cm^-2/0.1 mAh·cm^-2条件下稳定循环超过2 000 h。LFP/Li全电池在2.0 C倍率下的放电容量达111.11 mAh·g^-1，在0.5 C下循环800次后容量保持率为66.38%。本研究通过一种简单可行的双盐策略，协同提升了电解质的离子电导率与界面稳定性，为高能量密度固态锂金属电池的电解质设计提供了新思路。

关键词: F127, LiTFSI, LiDFOB, SEI, 界面稳定性, 离子电导率, 高能量密度

Abstract:

To address the poor interfacial stability between polyether-based solid electrolytes and lithium metal anodes， this study adopted a dual-salt strategy to design and prepare an F127/cellulose composite solid electrolyte. A homogeneous polymer slurry was fabricated by blending a LiTFSI and LiDFOB dual-salt system with F127 using a hot-melting method， which was then infiltrated into a porous cellulose membrane to obtain a structurally dense composite electrolyte. The results indicate that the introduction of LiDFOB significantly improves the electrolyte/lithium metal interface performance and promotes the formation of a stable solid electrolyte interphase （SEI） layer. Electrochemical tests reveal that the dual-salt electrolyte achieves an ionic conductivity of 2.0×10^-4 S·cm^-1 at 60 ℃ and an enhanced lithium-ion transference number of 0.31. Li/Li symmetric cells assembled with this electrolyte exhibit an increased limiting current density of 0.5 mA·cm^-2 and maintain stable cycling for over 2 000 h under the conditions of 0.1 mA·cm^-2 and 0.1 mAh·cm^-2. LFP/Li full cells deliver a discharge capacity of 111.11 mAh·g^-1 at a 2.0 C rate， with a capacity retention of 66.38% after 800 cycles at 0.5 C. This work provides a simple and feasible dual-salt strategy that synergistically enhances ionic conductivity and interfacial stability of the electrolyte， offering new insights for the design of electrolytes for high-energy-density solid-state lithium metal batteries.

Key words: F127, LiTFSI, LiDFOB, SEI, interfacial stability, ionic conductivity, high energy density

中图分类号:

TM911

游翔, 汤俊彦, 吴恙, 王玮, 王鑫昕, 易潇, 阳畅畅, 孔令慧, 张涛, 张刚. F127/纤维素复合固态电解质的双锂盐调控与电池性能研究[J]. 硅酸盐通报, 2026, 45(7): 2520-2530.

YOU Xiang, TANG Junyan, WU Yang, WANG Wei, WANG Xinxin, YI Xiao, YANG Changchang, KONG Linghui, ZHANG Tao, ZHANG Gang. Dual Lithium Salt Regulation and Battery Performance of F127/Cellulose Composite Solid Electrolyte[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(7): 2520-2530.

图/表 10

图1 双锂盐策略性能提升机理图

Fig.1 Mechanism diagram of performance enhancement via dual lithium salt strategy

图2 FLC、FLDC-1、FLDC-2和FLDC-3的电化学性能对比

Fig.2 Comparision of electrochemical performance of FLC， FLDC-1， FLDC-2， and FLDC-3

图3 双锂盐聚合物复合固态电解质的SEM照片

Fig.3 SEM images of dual lithium salt polymer composite solid electrolyte

图4 FLDC的应力-应变曲线

Fig.4 Stress-strain curve of FLDC

图5 FLC和FLDC复合固态电解质的物相结构、热化学与化学组成表征

Fig.5 Characterization of phase structure， thermal behavior， and chemical composition of FLC and FLDC composite solid electrolytes

图6 FLC和FLDC在Li/Li对称电池中的界面电化学行为表征

Fig.6 Characterization of interfacial electrochemical behavior of FLC and FLDC in Li/Li symmetric cells

图7 FLC和FLDC的Li/Li对称电池在0.1 mA·cm-2/0.1 mAh·cm-2条件下的长期循环性能对比

Fig.7 Long-term cycling performance comparison of Li/Li symmetric cells with FLC and FLDC under 0.1 mA·cm-2/0.1 mAh·cm-2conditions

图8 FLC和FLDC循环后Li/Li对称电池中锂金属表面的SEM照片

Fig.8 SEM images of lithium metal surface in lithium summetric cells after FLC and FLDC cycles

图9 FLC和FLDC Li/Li对称电池循环后锂金属表面SEI层的XPS化学组成对比分析

Fig.9 XPS comparative analysis of chemical composition of SEI layers on lithium metal surfaces after cycling in FLC and FLDC Li/Li symmetric cells

图10 LFP/FLC/Li和LFP/FLDC/Li全电池的电化学性能对比

Fig.10 Electrochemical performance comparison of LFP/FLC/Li and LFP/FLDC/Li full cells

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