RESUMO
Transition metal chalcogenides are considered as promising alternative materials for lithium-ion batteries owing to their relatively high theoretical capacity. However, poor cycle stability combined with low rate capacity still hinders their practical applications. In this work, the Cu-N chemical bonding directed the stacking Cu2-xSe nanoplates (DETA-Cu2-xSe) is developed to solve this issue. Such unique structure with small nanochannels can enhance the reactive site, facilitate the Li-ion transport as well as inhibit the structural collapse. Benefitting of these advantages, the DETA-Cu2-xSe exhibits high specific capacity, better rate capacity and long cyclability with the specific capacities of 565mAhg-1 after 100 cycles at 200 mA g-1 and 368mAhg-1 after 500 cycles at 5000 mA g-1. This novel DETA-Cu2-xSe structure with nanochannels is promising for next generation energy storage and the synthetic process can be extended to fabricate other transition metal chalcogenides with similar structure.
RESUMO
Transition metal oxides, as one of the most promising anode materials for lithium-ion batteries, often suffer from poor electronic conductivity and serious structural collapse. In this work, oxygen-vacancy-abundant CoFe2 O4 and NiFe2 O4 deposited on N-doped carbon nanosheets are designed and fabricated through a calcination procedure and a solvothermal strategy using Zn-hexamine coordination frameworks as precursors. The as-prepared NC@CoFe2 O4 and NC@NiFe2 O4 hybrids display improved cycle performances and rate capacities compared with CoFe2 O4 , NiFe2 O4 , and Fe2 O3 . The enhanced lithium storage performances of NC@CoFe2 O4 and NC@NiFe2 O4 are attributed to the oxygen vacancies and conductive N-doped carbon nanosheets, which increase the electronic conductivity and electrochemical reaction kinetics. The synthetic process in this work provides a new perspective for designing other high-performance transition metal oxide anodes.
