Molecular carbon skeleton with self-regulating ion-transport channels for long-life potassium ion batteries

作者：Feng, Wencong; Pan, Chuanqi; Wang, Hong; Zhang, Biluan; Luo, Wen^*; Shen, Chunli; Wang, Junjun; Cheng, Chaojie; Xv, Xianmin; Yu, Ruohan; Guo, Yanbing^*; Mai, Liqiang^*

来源：Energy Storage Materials, 2023, 63: 102975.

DOI：10.1016/j.ensm.2023.102975

• Self-regulating ion -transport channels
• Graphdiyne
• Potassium-ion batteries
• in situ TEM and Raman
• Molecular carbon skeleton

Developing anode materials with multiple-dimensional ion transport channels, especially to overcome huge volume expansion and sluggish ion diffusion kinetics caused by large radius of potassium ion (K+), is critical to improve the potassium storage performance. Herein, we propose a self-reversible conversion of chemical bonds with different bond lengths based on graphdiyne (GDY) to self-regulating the ion transport channels. Density functional theory (DFT) calculations and ex/in situ electrochemical tests proof the in-plane triangular-like pores (5.46 angstrom) of the GDY framework offer a transport channel for K+ (1.38 angstrom) diffusion in the direction perpendicular to the GDY plane, which differs it from carbonaceous materials whose ion diffusion is mostly governed by in-plane migration. Furthermore, the reversible alkyne-alkene bonds linking/breaking of GDY stimulated by K+ to realize self-regulating ion channels are demonstrated by in situ Raman and electro-kinetic analysis. Moreover, compared to graphite, the GDY anode with 2 orders of magnitude diffusion coefficient delivered a high reversible capacity of 202 mAh g- 1 at 100 mA g- 1 exhibited extraordinary durability corresponding to cycle time over 380 days. This work opens a new avenue of designing intelligent, efficient ion transport channels from molecular carbon skeleton perspective to enhance diffusion kinetic for high-performance KIBs.

• 单位
  武汉理工大学