Surface organic nitrogen-doping disordered biomass carbon materials with superior cycle stability in the sodium-ion batteries

To achieve widespread application of sodium-ion batteries (SIBs) in the future new energy market, developing electrode materials with low-cost sustainability and excellent electrochemical properties is imperative. Herein, a mesoporous N-doping palm leaf-based hard carbon (PLHC-N) anode with a high-rate and long lifespan is synthesized via an in-situ polymerization method by using palm leaf as the carbon precursor and polyaniline as the nitrogen source. Benefiting from the natural holey structure, the PLHC-N exhibits excellent Na+ storage capability with numerous ion transfer channels and a good volume buffer. Meanwhile, the N-doping materials improve ion and electron transferability and create more active sites for Na storage. Impressively, the PLHC-N sample shows an adsorption-intercalation-hole filling storage mechanism and affords an ultrahigh reversible capacity of 373 mAh g−1 at 25 mA g−1, and long-term cycle stability at 200 mA g−1 (∼95.0% retention upon 1000 cycles). Moreover, a full cell with a Na3V2(PO4)2F3 as cathode shows a favorable cyclability (112 mA h g−1 after 100 cycles at 0.5C (1C = 128 mA g−1) and a decent capacity retention of 90.1%). Given the cost effectiveness and material sustainability, our work provides novel strategy to design the hard carbon anode materials for advanced SIBs.