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Fabrication of a Mo‐Doped Strontium Cobaltite Perovskite Hybrid Supercapacitor Cell with High Energy Density and Excellent Cycling Life
Author(s) -
Tomar Anuj Kumar,
Singh Gurmeet,
Sharma Raj Kishore
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201801869
Subject(s) - cobaltite , materials science , capacitance , supercapacitor , electrode , power density , horizontal scan rate , analytical chemistry (journal) , chemical engineering , electrochemistry , chemistry , thermodynamics , metallurgy , physics , chromatography , engineering , cyclic voltammetry , power (physics)
Enriched with oxygen vacancies, Mo‐doped strontium cobaltite (SrCo 0.9 Mo 0.1 O 3− δ , SCM) is synthesized as an oxygen anion‐intercalated charge‐storage material through the sol–gel method. The supplemented oxygen vacancies, good electrical conductivity, and high ion diffusion coefficient bestow the SCM electrode with excellent specific capacitance (1223.34 F g −1 ) and specific capacity (168.88 mAh g −1 ) at 1 A g −1 . The decisive constant ( b ‐value) deduced for the charge storage mechanism (low scan‐rate region) is nearly 0.8, indicating a highly capacitive process. In the high scan‐rate region, however, the b ‐value is almost 0.5, and a linear pattern of charge ( q ) versus the inverse of the square root of the scan rate ( v −1/2 ) is obtained. The results reveal O 2− diffusion as the rate‐limiting factor for charge storage. Furthermore, a hybrid cell (SCM∥LRGONR) is fabricated by using lacey, reduced graphene oxide nanoribbon (LRGONR) as the negative electrode, which exhibits a high energy density (74.8 Wh kg −1 at a power density of 734.5 W kg −1 ). With a charging time of only 20.7 s, the cell sustains a very high energy density (33 Wh kg −1 ) with a high power delivery rate (6600 W kg −1 ). The excellent cycling stability (165.1 % activated specific capacitance retention and 97.6 % of the maximum value attained) after 10 000 charge–discharge cycles, demonstrates SCM is a potential electrode material for supercapacitors.