Retracted: Co₃O₄ Polyhedron@MnO₂ Nanotube Composite as Anode for High‐Performance Lithium‐Ion Batteries

Abstract

Abstract In this work, a novel lollipop nanostructure of Co 3 O 4 @MnO 2 composite is prepared as anode material in lithium‐ion batteries (LIBs). Cobalt metal–organic framework (ZIF‐67) is grown on the open end of MnO 2 nanotubes via a self‐assembly process. The obtained ZIF‐67@MnO 2 is then converted to Co 3 O 4 @MnO 2 by a simple annealing treatment in air. Scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction characterizations indicate that the prepared Co 3 O 4 @MnO 2 takes a lollipop nanostructure with a stick of ≈100 nm in diameter, consisting of MnO 2 nanotube, and a head part of ≈1 µm, consisting of Co 3 O 4 nanoparticles. The charge–discharge tests illustrate that this unique novel configuration endows the resulting Co 3 O 4 @MnO 2 with excellent electrochemical performances, delivering a capacity of 1080 mAh g −1 at 300 mA g −1 after 160 cycles, and 696 mAh g −1 at 1 A g −1 after 210 cycles, compared with 404 mAh g −1 and 590 for pure Co 3 O 4 polyhedrons and pure MnO 2 nanotubes at 300 mA g −1 after 160 cycles, respectively. The lollipop configuration consisting of porous Co 3 O 4 polyhedron and MnO 2 nanotube shows excellent structural stability and facilitates lithium insertion/extraction, leading to excellent cyclic stability and rate capacity of Co 3 O 4 @MnO 2 ‐based LIBs.