Phase Separation Derived Core/Shell Structured Cu₁₁V₆O₂₆/V₂O₅ Microspheres: First Synthesis and Excellent Lithium-Ion Anode Performance with Outstanding Capacity Self-Restoration

Novel amorphous vanadium oxide coated copper vanadium oxide (Cu₁₁V₆O₂₆/V₂O₅) microspheres with 3D hierarchical architecture have been successfully prepared via a microwave-assisted solution method and subsequent annealing induced phase separation process. Pure Cu₁₁V₆O₂₆ microspheres without V₂O₅ coating are also obtained by an H₂O₂ solution dissolving treatment. When evaluated as an anode material for lithium-ion batteries (LIBs), the as-synthesized hybrid exhibits large reversible capacity, excellent rate capability, and outstanding capacity self-recovery. Under the condition of high current density of 1 A g⁻¹, the 3D hierarchical Cu₁₁V₆O₂₆/V₂O₅ hybrid maintains a reversible capacity of ≈1110 mA h g⁻¹. Combined electrochemical analysis and high-resolution transmission electron microscopy observation during cycling reveals that the amorphous V₂O₅ coating plays an important role on enhancing the electrochemical performances and capacity self-recovery, which provides an active amorphous protective layer and abundant grain interfaces for efficient inserting and extracting of Li-ion. As a result, this new copper vanadium oxide hybrid is proposed as a promising anode material for LIBs.