Metal Sulfides@Carbon Microfiber Networks for Boosting Lithium Ion/Sodium Ion Storage via a General Metal-Aspergillus niger Bioleaching Strategy

The fabrication and design of electrodes that transfer more energy at high rates is very crucial for battery technology because of the increasing need for electrical energy storage. Usually, reducing a material's volume expansion and improving its electrical conductivity can promote electron and Li+/Na+ ion transfer in nanostructured electrodes and improve rate capability and stability. Here, we demonstrate a general metal-Aspergillus niger bioleaching approach for preparing novel fungus-inspired electrode materials that may enable high-performance lithium ion/sodium ion batteries with one-dimensional architectures. The fungus functions as a natural template to provide large amounts of nitrogen/carbon sources, which are functionalized with metal sulfide nanoparticles, yielding various metal sulfide nanoparticles/nitrogen-doped carbonaceous fibers (MS/NCF (MS = ZnS, Co9S8, FeS, Cu1.81S)) with high conductivity. In addition, the as-obtained MS/NCF has a uniform fiber architecture and abundant porous structure, which can also enhance the storage ability for LIBs and SIBs. Taking ZnS/NCF as an example, the material exhibits a high specific capacity of up to 715.5 mAh g(-1) (100 cycles) and 455 mAh g(-1)(50 cycles) at 0.1 A g(-1) for LIBs and SIBs, respectively. This versatile approach for employing a fungus as a sustainable template to form high-performance electrodes may provide a systematic platform for implementing advanced battery designs.