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Flexible Nitrogen‐Doped 2D Titanium Carbides (MXene) Films Constructed by an Ex Situ Solvothermal Method with Extraordinary Volumetric Capacitance
Author(s) -
Yang Chenhui,
Tang Yi,
Tian Yapeng,
Luo Yangyang,
Faraz Ud Din Muhammad,
Yin Xingtian,
Que Wenxiu
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201802087
Subject(s) - mxenes , materials science , capacitance , electrochemistry , capacitor , doping , titanium carbide , nitrogen , chemical engineering , titanium , electrode , supercapacitor , analytical chemistry (journal) , nanotechnology , optoelectronics , metallurgy , organic chemistry , chemistry , electrical engineering , engineering , voltage
A facile and controllable strategy, which combines solvothermal treatment with ex situ nitrogen doping by using urea saturated alcohol solution or monoethanolamine as nitrogen source, is used to prepare flexible, freestanding, and compact nitrogen‐doped delaminated Ti 3 C 2 (abbreviated N‐Ti 3 C 2 ) film electrodes for symmetric electrochemical capacitors (ECs). Compared with the N sites from in situ N solid solution doping, those of ex situ N solvothermal doping enable larger contributions to the capacitance through regulating nitrogen species and content. As a result, the urea‐assisted N‐Ti 3 C 2 (UN‐Ti 3 C 2 ) film exhibits an ultrahigh volumetric capacitance of 2836 F cm −3 (927 F g −1 ) at 5 mV s −1 in 3 m H 2 SO 4 solution. This value surpasses the all previously reported volumetric performance of MXenes. A large capacitance of 2643 F cm −3 (786 F g −1 ) is also obtained for the monoethanolamine‐assisted N‐Ti 3 C 2 film. In addition, the symmetric electrochemical capacitor fabricated from the binder‐free UN‐Ti 3 C 2 film exhibits a high volumetric energy density of 76 Wh L −1 , which is the highest value achieved compared to those of MXenes so far. This work presents the effects of nitrogen species and solvothermal treatment on the electrochemical performance of MXene, and opens up an exciting opportunity for fabricating highly flexible and integrated ECs.