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Novel Sub‐5 nm Layered Niobium Phosphate Nanosheets for High‐Voltage, Cation‐Intercalation Typed Electrochemical Energy Storage in Wearable Pseudocapacitors
Author(s) -
Wu Zeyi,
Jiang Le,
Tian Wenchao,
Wang Yanan,
Jiang Yingchang,
Gu Qinfen,
Hu Linfeng
Publication year - 2019
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.201900111
Subject(s) - materials science , supercapacitor , pseudocapacitor , niobium , niobium oxide , electrochemistry , nanosheet , intercalation (chemistry) , chemical engineering , electrolyte , energy storage , electrode , inorganic chemistry , nanotechnology , power (physics) , chemistry , physics , quantum mechanics , engineering , metallurgy
Layered niobium phosphates have been considered very promising energy storage materials because of their high theoretical operating voltage window and the rich oxidation states of niobium. However, their development has been stymied by the phase‐controlled synthesis due to the insolubility of niobium sources except in concentrated hydrofluoric (HF) acid systems. Herein, a new avenue is opened for layered acid niobium phosphate (2NbOPO 4 ·H 3 PO 4 ·H 2 O) synthesis in a mild oxalic acid system. Taking advantage of this strategy, in situ growth of sub‐5 nm 2NbOPO 4 ·H 3 PO 4 ·H 2 O nanosheet (NPene) arrays on conductive carbon fiber cloth (CFC) substrates is achieved as self‐standing electrodes for solid‐state supercapacitors. Interestingly, the NPene@CFC electrode exhibits a typical cation (H + or Li + )‐intercalation kinetics with a wide potential window of 0–1.0 V in aqueous electrolytes. Given the wide potential window and highly exposed active surface, the solid‐state asymmetric supercapacitors constructed from such a NPenes@CFC electrode display a high working potential of 2.0 V, energy density of 122.2 W h kg −1 at a power density of 589.7 W kg −1 , cycle stability with a capacitance retention of 94.2% after 10 000 cycles, and also outstanding flexible and wearable characteristics.