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Carbon‐Coated Na 3 V 2 (PO 4 ) 3 Supported on Multiwalled Carbon Nanotubes for Half‐/Full‐Cell Sodium‐Ion Batteries
Author(s) -
Chen Lei,
Zhong Zeqin,
Ren Shibin,
Han De-Man
Publication year - 2020
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.201901080
Subject(s) - electrochemistry , materials science , electrolyte , sodium , cathode , anode , diffusion , nanotube , electrode , analytical chemistry (journal) , chemical engineering , carbon nanotube , nanotechnology , chemistry , organic chemistry , physics , engineering , metallurgy , thermodynamics
Na‐ion superionic conductor (NASICON)‐based Na 3 V 2 (PO 4 ) 3 is regarded as a potential cathode for sodium‐ion batteries, due to the excellent thermal stability and large ion diffusion channel. Herein, multiwalled carbon nanotube–pierced Na 3 V 2 (PO 4 ) 3 (NVP@C/MWCNT) is synthesized through a simple sol–gel approach. Tested as a cathode for sodium‐ion half batteries, the as‐prepared electrode displays an excellent reversible capacity (111.6 mA h g −1 at 1 C) and superior rate capability (63.2 mA h g −1 at 80 C). Furthermore, in situ X‐ray diffraction (XRD) patterns of NVP@C/MWCNTs indicate the apparent two‐phase (de‐)sodiation process. In contrast, the ortho‐ disodium salts of tetrahydroxyquinone ( o ‐Na 2 C 6 H 2 O 6 ) are prepared as an anode, which demonstrates a reversible discharge capacity of 156.8 mA h g −1 at 0.1 C and enhanced high‐rate performance (72.1 mA h g −1 at 20 C) for sodium–organic half batteries. When evaluated as a Na‐ion full cell, a NVP@C/MWCNT || o‐ Na 2 C 6 H 2 O 6 full cell shows outstanding rate capability (33.3 mA h g −1 at 1.0 A g −1 ). Such impressive electrochemical behavior is related to the addition of multiwalled carbon nanotubes. This not only enhances electronic conductivity of NVP, but also inhibits the growth of grains, which shortens the Na + diffusion length and increases the contact space between electrode/electrolyte.