Modulating the Graphitic Domains and Pore Structure of Corncob-Derived Hard Carbons by Pyrolysis to Improve Sodium Storage

Abstract

Biomass-derived hard carbon materials are considered as the most promising anode materials for sodium-ion batteries (SIBs) due to their abundant sources, environmental friendliness, and excellent electrochemical performance. Although much research exists on the effect of pyrolysis temperature on the microstructure of hard carbon materials, there are few reports that focus on the development of pore structure during the pyrolysis process. In this study, corncob is used as the raw material to synthesize hard carbon at a pyrolysis temperature of 1000~1600 °C, and their interrelationationship between pyrolysis temperature, microstructure and sodium storage properties are systematically studied. With the pyrolysis temperature increasing from 1000 °C to 1400 °C, the number of graphite microcrystal layers increases, the long-range order degree rises, and the pore structure shows a larger size and wide distribution. The specific capacity, the initial coulomb efficiency, and the rate performance of hard carbon materials improve simultaneously. However, as the pyrolysis temperature rises further to 1600 °C, the graphite-like layer begins to curl, and the number of graphite microcrystal layers reduces. In return, the electrochemical performance of the hard carbon material decreases. This model of pyrolysis temperatures–microstructure–sodium storage properties will provide a theoretical basis for the research and application of biomass hard carbon materials in SIBs.

Recent progress on hard carbon and other anode materials for sodium-ion batteries

“…Song et al, used corncob as the raw material for hard carbon synthesis due the abundance of the by-product, which was pyrolyzed at temperatures between 1000 and 1600 °C [ 16 ]. The number of graphite microcrystal layers grows, the long-range order degree rises, and the pore structure exhibited a bigger size and wide distribution when the pyrolysis temperature climbs from 1000 °C to 1400 °C, resulting in the improved rate performance, initial coulomb efficiency, and specific capacity of hard carbon materials.…”

“…For instance, presodiation and co-doping with heteroatoms are amongst the approaches opted for. Presodiation was carried out to compensate the irreversible sodium consumption in HC upon initial charging and discharging (Qin et al, 2023; Fang et al, 2023) and whereas doping could tune the electronic configuration to improve the HC conductivity [ 16 ]. Moreover, deeper insights into the electrochemical mechanisms governing sodium storage, diffusion kinetics, and structural evolution during charge-discharge cycles have contributed to a better understanding of its performance which could be investigated through experimental and computational modelling.…”

MoS2/SnS/CoS Heterostructures on Graphene: Lattice-Confinement Synthesis and Boosted Sodium Storage

“…Rechargeable sodium-ion batteries (SIBs) were increasingly promising in the field of large-scale electric energy storage for renewable energy and smart grids during the “beyond-lithium-ion-batteries” era, due to the advantageous characteristics of low cost, high abundance, and wide distribution of sodium resources [ 1 , 2 , 3 , 4 ]. The larger radius of Na + (1.02 Å) than that of Li + (0.76 Å), however, results in the sluggish kinetics of insertion/extraction of Na + into active materials [ 5 , 6 , 7 ] and thus hinders the development and application of SIBs. The limitation has triggered a great deal of effort to develop numerous advanced anode nanomaterials for SIBs, such as carbon-based nanomaterials [ 8 , 9 , 10 , 11 ], metallic alloys [ 12 , 13 , 14 ], two-dimensional (2D) metal carbides (MXenes) [ 15 , 16 , 17 , 18 ], metal dichalcogenides [ 19 , 20 , 21 , 22 ], and metal sulfides.…”