Issue 9, 2018

Stable CoSe2/carbon nanodice@reduced graphene oxide composites for high-performance rechargeable aluminum-ion batteries

Abstract

Rechargeable aluminum-ion batteries (RAIBs) are regarded as the next generation of low-cost and high-capacity electrical energy storage systems. Compared to graphene-based cathodes, metal dichalcogenide cathodes can potentially provide RAIBs with higher capacities. However, metal dichalcogenides suffer from poor cycling performance, hindering the further development of high-capacity RAIBs. Thus, to further improve the performance of RAIBs, it is imperative to gain a deep understanding of the mechanisms behind the energy-storage and capacity-deterioration characteristics of these materials. In this work, we conducted detailed characterization to acquire a deep understanding of the energy storage mechanism of a CoSe2-based cathode. The characterization results revealed that energy storage involved incorporation of Al3+ into CoSe2 to generate AlmConSe2 (i.e., partial substitution of Co2+ by Al3+) and elemental Co, while capacity deterioration resulted from the dissolution of active cobalt species into the electrolyte and the pulverization of the CoSe2 phase. The understanding of the capacity-deterioration mechanism allowed us to design a two-step concept for a new type of RAIB composite cathode material. Thus, we employed a conductive wrapping layer of reduced graphene oxide (rGO) to protect CoSe2/carbon nanodice composites from cobalt dissolution and CoSe2 pulverization while also improving the conductivity of the materials. This novel design resulted in a CoSe2/carbon nanodice@rGO composite material with an outstanding cycling performance (after 500 cycles) of 143 mA h g−1 at 1000 mA g−1, which is one of the best performances for a metal-based RAIB cathode material reported to date. These findings are of great significance for the further development of high-capacity RAIBs.

Graphical abstract: Stable CoSe2/carbon nanodice@reduced graphene oxide composites for high-performance rechargeable aluminum-ion batteries

Supplementary files

Article information

Article type
Communication
Submitted
20 Mar 2018
Accepted
31 May 2018
First published
04 Jun 2018

Energy Environ. Sci., 2018,11, 2341-2347

Stable CoSe2/carbon nanodice@reduced graphene oxide composites for high-performance rechargeable aluminum-ion batteries

T. Cai, L. Zhao, H. Hu, T. Li, X. Li, S. Guo, Y. Li, Q. Xue, W. Xing, Z. Yan and L. Wang, Energy Environ. Sci., 2018, 11, 2341 DOI: 10.1039/C8EE00822A

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