Structural Design and Synthesis of an SnO₂ @C@Co-NC Composite as a High-Performance Anode Material for Lithium-Ion...

To overcome the drawbacks of the structural instability and poor conductivity of SnO₂ -based anode materials, a hollow core-shell-structured SnO₂ @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 SnO₂ nanoparticles and SnO₂ @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 SnO₂ 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 SnO₂ @C@Co-NC structure with superior energy density and durable lifespan is highly promising for the next-generation lithium-ion batteries.