Tubular nanoclay as effective ionic channels for hybrid conductive sodium metal anodes

Abstract

Sodium metal battery is expected to be employed for extensive energy storage owing to its high energy density and affordability. Nevertheless, a significant volume change may cause uneven stress distribution in Na anodes, leading to electrode pulverization and severe side effects. Herein, natural clay halloysite nanotubes with ionic conductivity were introduced to prepare hybrid sodium metal anodes (noted as Na@HNTs) by the melt infusion method and subsequent calendaring process. In Na@HNTs anode, a fast and continuous channel for electron and Na+ transport was created due to the presence of HNTs's ionic conductive phases at grain boundaries. Moreover, as-prepared Na@HNTs not only permits constant anode-level volume, but also simultaneously improves electrode surface chemistry. Na3V2(PO4)3 cathodes demonstrate excellent electrochemical performance in full cells with Na@HNTs anodes, displaying 80 mA h g−1 at 5C after 5000 cycles with 81.5% capacity retention. This work highlights the immense potential of utilizing natural clay as an effective ion diffusion channel for the development of hybrid sodium anodes.