Cross-Linked\nPVA/HNT Composite Separator Enables Stable\nLithium-Organic Batteries under Elevated Temperature

Abstract

Li-organic\nbatteries (LOBs) are promising advanced battery systems\nbecause of their unique advantages in capacity, cost, and sustainability.\nHowever, the shuttling effect of soluble organic redox intermediates\nand the intrinsic dissolution of small-molecular electrodes have hindered\nthe practical application of these cells, especially under high operating\ntemperatures. Herein, a cross-linked membrane with abundant negative\ncharge for high-temperature LOBs is prepared via electrospinning of\npoly­(vinyl alcohol) containing halloysite nanotubes (HNTs). The translocation\nof negatively charged organic intermediates can be suppressed by the\nelectronic repulsion and the cross-linked network while the positively\ncharged Li⁺ are maintained, which is attributed to the\nintrinsic electronegativity of HNTs and their well-organized and homogeneous\ndistribution in the PVA matrix. A battery using a PVA/HNT composite\nseparator (EPH-10) and an anthraquinone (AQ) cathode exhibits a high\ninitial discharge capacity of 231.6 mAh g^–1 and\nan excellent cycling performance (91.4% capacity retention, 300 cycles)\nat 25 °C. Even at high temperatures (60 and 80 °C), its\ncapacity retention is more than 89.2 and 80.4% after 100 cycles, respectively.\nOur approach demonstrates the potential of the EPH-10 composite membrane\nas a separator for high-temperature LOB applications.