Biotemplated Zinc Sulfide Nanofibers as Anode Materials for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have generated substantial interest because of the geopolitical uncertainty of the availability of lithium, as well as the potential cost savings associated with replacing lithium with sodium. One of the key technological impediments to SIBs is the availability of a high-capacity anode material. Here, we show that biotemplated zinc sulfide nanofibers, prepared using the M13 bacteriophage template, have the potential to be used for this purpose. We investigated the effect of both annealing and carbon coating on the electrochemical performance of these materials. Biotemplated zinc sulfide nanofibers, when coated with a few-nanometer carbon layer, could deliver a reversible capacity of 603 mAh/g at 100 mA/g discharge rate, even when the zinc sulfide loading is as high as 70%. The initial Coulombic efficiency reached 71%, and the electrode could be cycled for at least 100 cycles.