Issue 37, 2022

A high-energy conversion-type cathode activated by amorpholization for Li rechargeable batteries

Abstract

Although conversion-type electrodes deliver larger theoretical capacities than intercalation-type electrodes, their application as practical cathodes for Li rechargeable batteries is hindered by their intrinsically sluggish kinetics and low operating voltage. In this study, we demonstrate that the conversion-type electrochemical behaviors of Cu(PO3)2 in a Li-cell system are highly enhanced by amorpholization and carbon-mixing. In particular, the presence of the (PO3) polyanion in the structure enables a much higher operation voltage of Cu(PO3)2 relative to that of other conversion-type metal-oxide electrodes, resulting from the inductive effect by phosphorus with high electronegativity. As a result, the amorphorized Cu(PO3)2/C composite delivers not only a large reversible capacity of ∼240 mA h g−1 at 12 mA g−1 but also an average operation voltage of ∼2.8 V (vs. Li+/Li). Even at a high current density of 1200 mA g−1, up to ∼60% of the specific capacity at 12 mA g−1 is retained. Furthermore, the capacity retention after 300 cycles at 480 mA g−1 is ∼77% of the initial capacity. This outstanding power capability and cyclability of the amorphorized Cu(PO3)2/C composite differ markedly from the poor electrochemical properties of the well-crystallized Cu(PO3)2/C composites, indicating the enhanced kinetics of the conversion reaction in Cu(PO3)2 by amorpholization. In addition, the reversible conversion-reaction mechanism of Cu(PO3)2 in a Li-cell system is demonstrated through various experimental measurements.

Graphical abstract: A high-energy conversion-type cathode activated by amorpholization for Li rechargeable batteries

Supplementary files

Article information

Article type
Paper
Submitted
19 mar. 2022
Accepted
27 apr. 2022
First published
29 apr. 2022

J. Mater. Chem. A, 2022,10, 20080-20089

A high-energy conversion-type cathode activated by amorpholization for Li rechargeable batteries

Y. Lee, J. Kang, J. Ahn, W. Ko, H. Park, S. Lee, S. Lee, J. Yoo and J. Kim, J. Mater. Chem. A, 2022, 10, 20080 DOI: 10.1039/D2TA02167F

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