期刊
ENERGY & ENVIRONMENTAL SCIENCE
卷 11, 期 9, 页码 2341-2347出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c8ee00822a
关键词
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资金
- National Natural Science Foundation of China [21476264]
- Taishan Scholar Foundation [tsqn20161017, ts20130929]
- Fundamental Research Funds for the Central Universities [18CX05007A, 15CX08009A, R1704017A]
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.
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