Tailoring porous structure and graphitic degree of seaweed-derived carbons for high-rate performance lithium-ion batteries

Abstract

Hierarchical porous carbons embedded with graphitic domains were synthesized by carbonization of seaweeds with a catalytic graphitization strategy. The Ni2+ ions are pre-chelated with seaweeds precursor (porphyra) to enable a catalyst confined graphitization process and to provide mesopores template. Carbonization temperature is significant in tailoring graphitic degree and porosity structure of porphyra-derived carbons (PDCs). The PDCs carbonized at 900 °C (PDC-900) show favorable features for electrochemical energy storage, which balance the specific surface area (515.7 mm2g-1), degree of graphitization (ID/IG = 0.78), expand graphite interlayer spacing (∼0.342 nm), and N-doping (2.13 wt%). These unique features of PDC-900 not only can supply abundant sites for the storage and insertion of Li ions, but also can facilitate rapid mass transport of electrons and Li ions. Thus, PDC-900 shows remarkable reversible capacity (950 mAhg−1 at 0.1 C), excellent rate capability (352 mAhg−1 at 10 Ag-1), and superior cycling performance (348 mAhg−1 at 5 Ag-1 after 3000 cycles), when used as an anode material for lithium ion batteries.