Dual Lithium Salt Regulation and Battery Performance of F127/Cellulose Composite Solid Electrolyte

doi:10.16552/j.cnki.issn1001-1625.2025.1208

Abstract

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

CLC Number:

TM911

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.

Figures/Tables 10

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

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

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

Fig.4 Stress-strain curve of FLDC

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

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

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

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

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

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

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