Regulation of collagen-derived carbon material structures through in-situ precipitation templating for fast sodium storage

Limited capacity with sluggish Na+ diffusion kinetics limits the application of carbon anodes in sodium ion batteries (SIB). Herein, we present a straightforward approach for fabricating porous carbons with delicate structural regulation using collagen fibers as precursor, in-situ generated Mg(OH)2 as template. The utilization of small-sized Mg(OH)2 facilitates the formation of mesopores further to enhance the diffusion kinetics of Na⁺. The collagen fiber precursors contain abundant N and S elements, resulting in N, S co-doping. Leveraging the absorption mechanism facilitated by rapid charge transfer, the synthesized porous carbon exhibits exceptional SIB performance in ether-based electrolytes: a capacity of 459 mAh g−1 at 0.05 A g−1 and 125 mAh g−1 at 50 A g−1; a capacity of 128 mAh g−1 with an average Coulombic efficiency of ≈99 % and a decay rate of 0.0072 % per cycle after 5000 cycles at 10 A g−1. Coupled with Na3V2(PO4)3 cathode, the fabricated full cell also demonstrates a high specific capacity of 290 mAh g−1 at 0.2 A g−1 with an initial Coulombic efficiency of 75.6 %. These findings offer an effective and practical strategy for the fabrication of porous carbon materials and the advancement of SIB through the development of advanced carbon anodes.