Free-Standing N-Doped Carbon Nanotube Films with Tunable Defects as a High Capacity Anode for Potassium-Ion Batteries

Abstract

Potassium-ion batteries (KIBs) have aroused enormous interest for future energy storage technology. However, the current anodes for KIBs greatly suffer from the rapid capacity fading and inferior rate capability. Herein, a free-standing flexible anode, that is, nitrogen-doped carbon nanotube paper (NCTP), which is derived from the pyrolysis of organic polypyrrole materials, is demonstrated for high-performance potassium storage. The correlations between the material structure and electrochemical properties have been investigated by a series of material analysis and characterizations, as well as electrochemical tests. The research results show that the annealing temperature dramatically affects the N-doping content, the carbon defects, and the graphitization degree. Electrochemical tests indicate that the NCTP annealed at 700 °C displays the best performances with a high reversible capacity of 250.1 mA h g–1 at 100 mA g–1 and superior rate capability retaining 133 mA h g–1 at 5 A g–1. The excellent electrochemical properties are derived from a synergic contribution from the moderate N-doping, carbon defect, and high electronic conductivity of the materials. The facile pyrolysis strategy and the appealing performances involved in this work could provide some hints to manipulate high-performance anode materials of KIBs.

A review of hard carbon anode: Rational design and advanced characterization in potassium ion batteries

“…Liu's group prepared N‐doped carbon nanotube films with tunable defects as a free‐standing anode for KIBs. They found that changing the pyrolysis temperature could optimize the degree of graphitization, the relative amount of defects, and the N doping level in the N‐doped carbon nanotube films 79 . As a result of the synergic contribution from the interconnected structure, high content of N doping, abundant carbon defects, and the optimized graphitization of the tubular carbon fibers, the as‐prepared free‐standing electrode achieved an outstanding electrochemical performance in KIBs.…”

Design of Flexible Films Based on Kinked Carbon Nanofibers for High Rate and Stable Potassium-Ion Storage

“…Compared with the reported carbon-based PIBs anode materials, the S/N-KCNFs demonstrated relatively higher rate performance (Fig. 5e) [17,37,40,[44][45][46][47][48][49][50][51][52]. In addition, the specific capacity is 330 mAh g −1 at a constant current of 1000 mA g −1 and the capacity retention rate reaches 93.3% after 2000 cycles of charge-discharge cycle test (Figs.…”

Prospects of Electrode Materials and Electrolytes for Practical Potassium‐Based Batteries

“…Except for graphite, various carbonaceous materials (soft carbon, [162,[165][166][167][168][169][170][171][172][173] hard carbon, [74,[174][175][176][177][178][179][180][181][182][183][184][185][186][187][188] heteroatomic doped carbon, [189][190][191][192][193][194][195][196][197][198][199][200][201][202][203][204][205][206][207] graphitic carbon [164,[208][209][210][211]…”