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.