Graphitic carbon with increased interlayer spacing derived from low-temperature CO2 rapid conversion for high-performance potassium storage

Abstract

Graphitic carbon has been emerged as one of the most promising anode materials for potassium-ion batteries (PIBs) due to its moderate theoretical specific capacity, high electrical conductivity, and outstanding chemical stability. However, the structure of graphitic carbon usually experiences irreversible damage during the charge and discharge process, primarily due to the large radius of potassium ion. In contrast to the traditional preparation methods, we develop a low-carbon approach to obtain graphitic carbon with larger lattice spacing via a rapid chemical conversion between CO₂ and NaAlH₄ at ∼62 °C. We confirm that the CO₂/NaAlH₄ ratio plays a crucial role in increasing the degree of graphitization and promoting the formation of a flaky morphology of carbon materials. When applied as an anode material for potassium storage, the prepared graphitic carbon exhibits outstanding cycling stability and rate performance. It maintains a reversible capacity of 210 mAh g⁻¹ after 1000 cycles at a current density of 0.1 A g⁻¹, with a capacity retention rate of 95.9 %. This efficient method of preparing graphitic carbon provides valuable inspiration for the development of advanced energy storage materials.