NiO@MnO₂ core–shell composite microtube arrays for high-performance lithium ion batteries

Abstract

Tubular array structures are very attractive for electrochemical energy storage and conversion systems due to their unique physicochemical properties. Herein, a NiO microtube array is fabricated via a facile oxalic acid corrosion method followed by heat treatment. A NiO@MnO 2 core-shell composite microtube array is further achieved by the anodic electrodeposition using the NiO microtube array as substrate. When applied as self-supported electrode for lithium ion batteries (LIBs), the NiO@MnO 2 core-shell composite microtube array electrode shows excellent lithium storage properties. The electrode delivers a reversible capacity of 510 mA h g À1 at a high rate of 5.1 A g À1 , showing its good rate capability. In particular, a reversible capacity of 1573 mA h g À1 is observed after 500 cycles at a current density of 0.53 A g À1 , demonstrating the superior cycling performance of the electrode. The electrodeposited MnO 2 layer as a protective shell prevents the NiO microtubes from deformation during electrochemical cycling, responsible for the superior cycle stability of the NiO@MnO 2 core-shell composite microtube array electrode. The prominent lithium storage performance of the composite microtube array electrode can be attributed to its unique structure characteristics.

MOF-Derived Hierarchical MnO-Doped Fe3O4@C Composite Nanospheres with Enhanced Lithium Storage

“…As indicated in Figure S7, the increase of discharge capacity with the electrochemical cycling mainly occurs at relatively low voltages (<0.8 V). This shows that the reversible formation of a polymeric gel-like film may lead to the extra capacity of the electrode, which is a usual phenomenon for the nanostructured TMO anodes for LIBs. ,− Figure S8 shows the TEM images of the hierarchical MnO-doped Fe 3 O 4 @C nanospheres after 200 cycles at 200 mA g –1 . Obviously, the hierarchical nanosphere structure of the MnO-doped Fe 3 O 4 @C composite is well retained after 200 cycles.…”