All-cellulose gel electrolyte with black phosphorus based lithium ion conductors toward advanced lithium-sulfurized polyacrylonitrile batteries

Sulfurized polyacrylonitrile (SPAN) have been regarded as a promising cathode in high-energy-density lithium-sulfur batteries. However, severe safety issues derived from the electrolyte leakage and the uncontrollable lithium dendrite growth have seriously hindered the practical usage of Li-SPAN batteries. To address these issues, an eco-friendly and porous cellulose gel electrolyte (GE) was designed and prepared by UV photopolymerization and phase inversion methods. Also, covalent functional black phosphorous nanosheets (denoted as BP-Li) were fabricated and chosen as superior Li+ conductors in cellulose GE, ensuring the rapid ion transmission and suppressing the growth of lithium dendrites. As expected, the cellulose/BP-Li GE exhibited satisfactory ionic conductivity up to 5.21 × 10-3 S cm-1 with the high lithium ion transference number of 0.72. The Li-SPAN battery assembled with cellulose/BP-Li GE delivered high capacity of 938.8 mAh g-1 after 500 cycles with the capacity retention of 72.8 %. Hence, the cellulose/BP-Li GE displayed its promising usage in Li-SPAN batteries.