A Hierarchical Nano-SiO2-Supported Gel Polymer Electrolyte Realizes Good Compatibility Of Organic Liquid Electrolyte And Lithium Metal

Associate Professor Mingtao Li ,Wei Tang from Xi'an Jiaotong University teamed up with Nobel Laureate in Chemistry and Professor John Bennings Goodenough of the University of Texas at Austin to jointly develop a nano-SiO₂-supported gel polymerization Electrolyte (SiO₂-GPE), which has upgraded the traditional organic liquid electrolyte and solved the problem of its compatibility with lithium metal.

The nano-SiO₂-supported gel polymer electrolyte (SiO₂-GPE) with a hierarchical structure fabricated via in situ gelation of a traditional organic liquid electrolyte supported on a functionally modified SiO₂ layer, which displayed high ionic conductivity (1.98 × 10^–3 S cm^–1 at 25 °C) and wide electrochemical window (>4.9 V vs Li/Li⁺).

Moreover, SiO₂-GPE has good compatibility with lithium metal, which can effectively inhibit the growth of lithium dendrites.

Thanks to the highly compatible electrode/electrolyte interface and the inhibition of lithium dendrites provided by the synergistic effect of this composite gel electrolyte, the cycle performance and Coulomb efficiency of lithium metal batteries have been significantly improved, and this has also been tested by researchers prove.

Experiments show that based on this electrolyte, a lithium metal battery with LiFePO₄ as the positive electrode shows a high discharge specific capacity of 162.9 mAh g^-1 after 200 cycles at 0.1C rate, and the capacity retention rate after 200 cycles is 99.75%; At a high rate of 1 C, it still shows a high capacity of 125.5 mAh g^-1, and its capacity retention rate is 88.42% after 700 cycles, with excellent electrochemical performance.

This work provides a new strategy to solve the problem of interfacial matching between lithium metal and traditional organic liquid electrolytes, and provides a direction for the development of high-density lithium metal batteries for organic electrolyte systems. 

References: Pu Yang, Xiangwen Gao, Xiaolu Tian, Chengyong Shu, Yikun Yi, Pei Liu, Te Wang, Long Qu, Bingbing Tian, et al. Upgrading Traditional Organic Electrolytes toward Future Lithium Metal Batteries: A Hierarchical Nano-SiO2-Supported Gel Polymer Electrolyte.[J]ACS Energy Lett. 2020.DOI: 10.1021/acsenergylett.0c00412.