A novel construction of Ti3C2@complete edge-nitrogen doped carbon spheres with excellent K-ion storage performance

• Published in: Nano energy Vol. 97; p. 107161
• Main Authors: Cao, Yaping, Huang, Rui, Qin, Shengyu, Chen, Hui, Shen, Yupeng, Zhang, Lanying, Zhang, Yelong, Wang, Qian, Guo, Shaojun, Yang, Huai
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.06.2022
• Subjects: Carbon materials; Edge nitrogen doped; K-ion batteries; Ti3C2 nanosheets; Edge nitrogen doped; K-ion batteries; Carbon materials; Ti3C2 nanosheets
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2022.107161

Edge nitrogen doping, including pyridinic and pyrrolic nitrogen, is an effective strategy to enhance the electrochemical performance of carbons for K-ion batteries owing to the abundant defective sites and lower K-ion adsorption energy than graphitic nitrogen. Nevertheless, due to the singleness of precursor and imprecise carbonization conditions, designing complete edge-nitrogen doped carbonaceous materials is still a grand challenge. Herein, we design a precise controlled pyrolysis strategy of the self-assembled Ti3C2 @melamine-E7 microcapsules (E7: one of the liquid crystals). This method leads to a complete edge nitrogen (100 at% edge nitrogen out of 15.07 at% nitrogen) doped Ti3C2-carbon double-shell hollow microsphere (NTC-HM). To date, such complete edge nitrogen doping level is the highest among the reported nitrogen doped carbon materials. We find that the NTC-HM, as anode for K-ion batteries, demonstrates an outstanding reversible capacity of 436.6 mAh/g of 0.1 A/g over 150 cycles and high capacity retention of 81.3% (Cycle 500/Cycle 3) under 1.0 A/g, which is among the best in all the excellent carbonaceous electrodes for K-ion batteries. Also, a full cell assembled perylenetetracarboxylic dianhydride (PTCDA) cathode and NTC-HM anode delivers a practical energy density of 126.9 Wh/kg under 0.2 A/g. The complete edge nitrogen doped level was firstly achieved by the precise pyrolysis regulation of Ti3C2 @melamine-E7 microcapsules. The as-prepared NTC-HM, possessing unique double-shell structure with the inner carbon layer and the outer Ti3C2 nanosheets, exhibited superior practical energy density of 126.9 Wh/kg under 0.2 A/g as for the anode of the full cell with PTCDA cathode. [Display omitted] •The complete edge nitrogen doped level was firstly achieved by the precise pyrolysis regulation of Ti3C2 @melamine-E7 microcapsules.•The obtained hollow carbon spheres possessed unique double-shell structure with the inner carbon layer and the outer Ti3C2 nanosheets.•The as-prepared NTC-HM exhibited superior practical energy density of 126.9 Wh/kg under 0.2 A/g as for the anode of full cell with PTCDA cathode.