Enhancing Li+ transport via a nanoporous cellulose fiber membrane with an anion-sorbent for high-performance lithium-ion batteries

Abstract

Cellulose fiber membranes have been of great interest in the battery research community due to their excellent electrolyte affinity and thermal stability. However, they have long been plagued by issues such as unevenly distributed large pores and poor mechanical strength. In this study, we employed a unique method combining cellulose partial dissolution, phase separation, and in situ growth of zeolitic imidazolate frameworks (ZIFs) to optimize the pore structure of cellulose fiber membranes, and successfully fabricated a uniform nanoporous cellulose composite membrane. The optimized cellulose composite membrane demonstrated outstanding performance, including higher porosity (63.7%), electrolyte absorption (432%), and ion conductivity (1.43 mS cm⁻¹), lower interfacial resistance (87 Ω), and lower desolvation activation energy (56.1 KJ mol⁻¹). ZIF nanoparticles as an anion-sorbent grown on the nanoporous surface can enhance lithium-ion transportation and alleviate the decomposition of anions. Most importantly, the LiFePO₄/membrane/Li cell assembled with this cellulose composite membrane showed excellent cycling stability with a capacity retention of 95% after 300 cycles at a current density of 1C. We anticipate that this work could promote the applications of sustainable cellulose fiber membranes in the battery industry in the future.