Research progress of carbon-based sodium storage anode materials

• 1、College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106

Abstract：Sodium-ion batteries (SIBs) show remarkable potential for large-scale energy storage applications due to their abundant resources, low cost, excellent safety, and environmental friendliness. Among many anode materials, hard carbon stands out as a strong candidate for anode materials for SIBs due to its readily available raw materials, stable structural properties, and excellent conductivity. The properties of hard carbon are significantly affected by the selection of its precursor, the method of pretreatment, and the pyrolysis temperatureResearch progress of carbon-based sodium storage anode materials. To optimize the performance of hard carbon, researchers have adopted various modification strategies, including but not limited to fine-tuning the pore structure, defect degree, and layer spacing, screening the suitable electrolyte, and implementing the pre-sodiumation treatment. Regarding the mechanism of sodium storage in hard carbon, the academic community has not yet reached a consensus, and the main theories include "intercalation-filling", "adsorption-intercalation", "adsorption-filling", and "adsorption/intercalation". "adsorption/intercalation-filling" models. In this paper, we systematically review the development of SIBs and the latest research trends of hard carbon anode materials, with special emphasis on an in-depth investigation of the influence of the hard carbon microstructure on the sodium storage behavior, as well as the development of a more comprehensive and in-depth understanding of the mechanism on this basis, which is of great academic and practical significance for guiding the rational design of hard carbon materials and the fabrication of SIBs with excellent performance.

Keywords： Materials science Sodium ion battery Hard carbon cathode material Sodium storage mechanism