Biomimetic-Mineralization-Assisted Self-Activation Creates a Delicate Porous Structure in Carbon Material for...

Porous carbons have shown their potential in sodium-ion batteries (SIBs), but the undesirable initial Coulombic efficiency (ICE) and rate capability hinder their practical application. Herein, learning from nature, we report an efficient method for fabricating a carbon framework (CK) with delicate porous structural regulation by biomimetic mineralization-assisted self-activation. The abundant pores and defects of the CK anode can improve the ICE and rate performance of SIBs in ether-based electrolytes, whereas they are confined in carbonate ester-based electrolytes. Notably, ether-based electrolytes enable CK anode to possess excellent ICE (82.9%) and high-rate capability (111.2 mAh g^-1 at 50 A g^-1). Even after 5500 cycles at a large current density of 10 A g^-1, the capacity retention can still be maintained at 73.1%. More importantly, the full cell consisting of the CK anode and Na₃V₂(PO₄)₃ cathode delivers a high energy density of 204.4 Wh kg^-1, with a power density of 2828.2 W kg^-1. Such outstanding performance of the CK anode is attributed to (1) hierarchical pores, oxygen doping, and defects that pave the way for the transportation and storage of Na⁺, further enhancing ICE; (2) a high-proportion NaF-based solid-electrolyte-interphase (SEI) layer that facilitates Na⁺ storage kinetics in ether-based electrolytes; and (3) ether-based electrolytes that determine Na⁺ storage kinetics further to dominate the performance of SIBs. These results provide compelling evidence for the promising potential of our synthetic strategy in the development of carbon-based materials and ether-based electrolytes for electrochemical energy storage.