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Reversible Cu 4 O 3 Phase Formation in CuO Nanoplate Anodes for High Capacity and High Coulombic Efficiency
Author(s) -
Radhakrishnan Arya,
Gangaja Binitha,
Nair Shantikumar,
Santhanagopalan Dhamodaran
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201702487
Subject(s) - faraday efficiency , materials science , anode , phase (matter) , ion , electrode , analytical chemistry (journal) , chemical engineering , chemistry , organic chemistry , engineering , chromatography
Conversion materials with high specific capacity are of interest to improve energy density of Li‐ion batteries. Here, we present results concerning hydrothermally synthesized CuO nanoplates that exhibit high specific capacity of 800 and 698 mAh/g at C/2 and 1C rates respectively and 180 mAh/g at a high rate of 30C. The electrodes exhibit high Coulombic efficiencies of about 66% and 60% at C/2 and 1C rate respectively, these are high efficiency values compared to the ones reported in the literature at respective rates. To understand the high performance, ex situ x‐ray diffraction at different states of first discharge/charge is utilized that shine light on the lithiation/delithiation pathways of the CuO nanoplates. Lithiation proceeds through multiple phase transition CuO → Cu 4 O 3 → Cu 2 O → Cu and it was found that Cu 4 O 3 is reversible at the end of first charge. Cu and residual Cu 2 O was observed at the end of lithiation along with Li 2 O and Li 2 O 2 phases. At the end of first charge, Cu 4 O 3 phase along with CuO was observed as a major end‐product with relatively minor concentrations of Cu 2 O. Cu 4 O 3 as a major constituent observed in composite electrode seems to be the key information that can explain good reversibility and high Coulombic efficiency reported in the present work.