Novel amorphous vanadium oxide coated copper vanadium oxide (Cu11 V6 O26 /V2 O5 ) microspheres with 3D hierarchical architecture have been successfully prepared via a microwave-assisted solution method and subsequent annealing induced phase separation process. Pure Cu11 V6 O26 microspheres without V2 O5 coating are also obtained by an H2 O2 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 Cu11 V6 O26 /V2 O5 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 V2 O5 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.
Keywords: Cu11V6O26/V2O5 hybrid; amorphous vanadium oxide coating; capacity self-restoration; lithium-ion batteries.
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