Hierarchically porous closed-pore hard carbon as a plateau-dominated high-performance anode for sodium-ion batteries

• Published in: Chemical communications (Cambridge, England) England), 2024-03, Vol.6 (22), p.371-374
• Main Authors: Nagmani, Manna, S, Puravankara, S
• Format: Article
• Language: English
• Subjects: Anodes; Graphene; Interlayers; Porosity; Sodium; Sodium-ion batteries
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/d4cc00025k

Micro-spherical hard carbons (MSHCs) with distinct porosity features have been synthesized from an easy microwave-assisted solvothermal pre-treatment of sucrose, followed by carbonization, as anodes for sodium-ion batteries. The MSHC exhibits large interlayer spacing of turbostratic graphene nanosheets with more defective graphene planes, hierarchical pore structures, and closed pores. The MSHC anode delivered a high reversible capacity of 422 mA h g −1 at 0.1C rate with a low-potential battery-like plateau contribution of 57%, which is the best reported reversible sodium storage performance to date for an unmodified HC for SIBs. The MSHC shows 251 and 140 mA h g −1 high-rate capacities at 1C and 5C, respectively, with excellent capacity retention of 84% after 500 cycles at 1C. GITT and EPR measurements confirm the storage mechanism shift from intercalation to the quasi-metallic sodium clusters in the closed pores at low potentials. The full cell with the MSHC anode and a P2-Na 0.67 Ni 0.33 Mn 0.67 O 2 (NNMO) cathode delivered a high energy density of 292 W h kg −1 at a working potential of 3.2 V. Sucrose-derived micro spherical hard carbon with diverse porosity and closed pores exhibits an excellent reversible capacity of 251 mA h g −1 at 1C and capacity retention of 84% after 500 cycles.