Regulating potassium storage kinetics in mesoporous carbon spheres via delicate inner structural design

• Published in: Applied surface science 2024-07, Vol.660, p.160019, Article 160019
• Main Authors: Liu, Chang, Zhao, Yutong, Dai, Yao, Fan, Huilin, Zheng, Hongkui, Zheng, Runguo, Wang, Zhiyuan, Sun, Hongyu, Liu, Yanguo
• Format: Article
• Language: English
• Subjects: Inner-shell structure; Ion diffusion; Mesoporous carbon spheres; Potassium ion batteries; Pseudo-capacitance
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.160019

The internal morphology and structure of mesoporous carbon spheres are successfully controlled by changing the pore geometry of the initial sacrificing templates. The optimized sample shows a comprehensive potassium storage performance, which is ascribed to the balancing of pseudo-capacitance-controlled process and diffusion-controlled process. [Display omitted] •Mesoporous carbon spheres (MCSs) are synthesized by sacrificed template method.•The internal morphology and structure of the MCSs are well controlled.•The optimized sample shows excellent potassium storage performance.•The good electrochemical performance is ascribed to the delicate inner structural design. Carbon materials have been considered to be potential anodes for potassium-ion batteries (PIBs). Different strategies, including designing micro-/nano-structure and porous morphology, introducing heteroatom doping, and creating carbon-based hybrids, have been employed to improve the potassium ion transport kinetics. Nevertheless, it is still a challenge to achieve satisfactory potassium storage performance due to the uncontrolled reaction kinetics of the large-sized potassium ions. Herein, we successfully synthesized mesoporous carbon spheres (MCSs) with tunable internal morphology and structure by using sacrificed template method. The optimized MCSs with novel half inner-shell structures (HIS-MCSs) show excellent electrochemical performance when used as the anode for PIBs. Specifically, a reversible specific capacity of 241.2 mAh/g is achieved at a current density of 0.1 A/g. Even at 5.0 A/g, a reversible specific capacity of 120 mAh/g can still be reached. Long-term stability tests show that the electrode holds a capacity of 166.5 mAh/g after 1000 cycles at 1.0 A/g. The good cycling stability and rate performance of the HIS-MCSs electrode are attributed to the well-defined inner structural design, in which the contribution from ion diffusion and pseudo-capacitance process are compromised.