Structural Design and Synthesis of an SnO2@C@Co-NC Composite as a High-Performance Anode Material for Lithium-Ion Batteries
Graphical Hollow core–shell anode : An SnO 2 @C@Co-NC anode material with hollow core–shell structure was structurally designed and synthesized by a heteroatom-doping and multiconfinement approach. This material can efficiently alleviate the volume expansion of the SnO 2 -based anode materials and exhibits much-enhanced electrochemical performance, including high rate performance and cycle stability, as well as superior capacity. To overcome the drawbacks of the structural instability and poor conductivity of SnO 2 -based anode materials, a hollow core–shell-structured SnO 2 @C@Co-NC (NC=N-doped carbon) composite was designed and synthesized by employing the heteroatom-doping and multiconfinement strategies. This composite material showed a much-reduced resistance to charge transfer and excellent cycling performance compared to the bare SnO 2 nanoparticles and SnO 2 @C composites. The doped heteroatoms and heterostructure boost the charge transfer, and the porous structure shortens the Li-ion diffusion pathway. Also, the volume expansion of SnO 2 NPs is accommodated by the hollow space and restricted by the multishell heteroatom-doped carbon framework. As a result, this structured anode material delivered a high initial capacity of 1559.1 mA h g −1 at 50 mA g −1 and an initial charge capacity of 627.2 mA h g −1 at 500 mA g −1 . Moreover, the discharge capacity could be maintained at 410.8 mA h g −1 after 500 cycles with an attenuation rate of only 0.069 % per cycle. This multiconfined SnO 2 @C@Co-NC structure with superior energy density and durable lifespan is highly promising for the next-generation lithium-ion batteries.
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