Premium
Large‐Area, Uniform, Aligned Arrays of Na 3 (VO) 2 (PO 4 ) 2 F on Carbon Nanofiber for Quasi‐Solid‐State Sodium‐Ion Hybrid Capacitors
Author(s) -
Mao Zhifei,
Wang Rui,
He Beibei,
Gong Yansheng,
Wang Huanwen
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201902466
Subject(s) - materials science , quasi solid , electrolyte , anode , supercapacitor , cathode , carbon nanofiber , sodium ion battery , electrode , electrochemistry , intercalation (chemistry) , vanadium , chemical engineering , nanotechnology , analytical chemistry (journal) , inorganic chemistry , chemistry , carbon nanotube , engineering , faraday efficiency , dye sensitized solar cell , metallurgy , chromatography
Sodium–vanadium fluorophosphate (Na 3 V 2 O 2 x (PO 4 ) 2 F 3−2 x , NVPF, 0 ≤ x ≤ 1) is considered to be a promising Na‐storage cathode material due to its high operation potentials (3.6–4 V) and minor volume variation (1.8%) during Na + ‐intercalation. Research about NVPF is mainly focused on powder‐type samples, while its ordered array architecture is rarely reported. In this work, large‐area and uniform Na 3 (VO) 2 (PO 4 ) 2 F cuboid arrays are vertically grown on carbon nanofiber (CNF) substrates for the first time. Owing to faster electron/ion transport and larger electrolyte–electrode contact area, the as‐prepared NVPF array electrode exhibits much improved Na‐storage properties compared to its powder counterpart. Importantly, a quasi‐solid‐state sodium‐ion hybrid capacitor (SIHC) is constructed based on the NVPF array as an intercalative battery cathode and porous CNF as a capacitive supercapacitor anode together with the P(VDF‐HFP)‐based polymer electrolyte. This novel hybrid system delivers an attractive energy density of ≈227 W h kg −1 (based on total mass of two electrodes), and still remains as high as 107 Wh kg −1 at a high specific power of 4936 W kg −1 , which pushes the energy output of sodium hybrid capacitors toward a new limit. In addition, the growth mechanism of NVPF arrays is investigated in detail.