Multi-shelled Ni₆MnO₈ hollow microspheres for high-performance supercapacitors

Abstract

Binary transition metal oxides have attracted tremendous interest for their excellent redox activity and large natural abundance. They could achieve distinct electrochemical properties by engineering special hollow structures. In this work, we have synthesized triple-shelled Ni 6 MnO 8 hollow microspheres constructed with nanosheets through step by step adsorption of the corresponding metal ions on carbon spheres followed by calcination in air. The as-prepared Ni 6 MnO 8 hollow microspheres with nanosheet shells have an average diameter of~900 nm, with a large surface area of 145.011 m 2 g −1 . They exhibit outstanding capacitive performance as electrode materials, including high specific capacitance (1380 F g −1 at 1 A g −1 ), distinguished rate capability (68% capacity retention at ultrahigh 100 A g −1 ) and stable cycling property (98% retention rate at 10 A g −1 after 5000 cycles), which are superior to those of the Ni 6 MnO 8 hollow microspheres with nanoparticle shells. Furthermore, the assembled Ni 6 MnO 8 -NS//AC asymmetric supercapacitor demonstrates a high energy density (31.8 W h kg −1 at 750 W kg −1 ) with a high capacity retention of 93% even after 10,000 cycles. The distinguished performances can be attributed to the synergy of binary metals and the unique hollow structure with nanosheet shells.

Solution combustion synthesis of Ni-based hybrid metal oxides for oxygen evolution reaction in alkaline medium

“…6c ). 51 The fitting of Mo 3d spectrum of Ni x Mo 1− x O y revealed two spin–orbit doublets, characteristic of Mo 5+ and Mo 6+ ( Fig. 6d ).…”

Investigating the Potential Use of Ni‐Mn‐Co (NMC) Battery Materials as Electrocatalysts for Electrochemical Water Splitting

“…[76] Previous work has shown that Ni(OH) 2 can also partially convert into NiO upon repetitive cycling in the OER region. [77] TEM characterisation of the electrode after cycling (Figure S8) demonstrated that the crystalline state was maintained with lattice spacings of 0.20 and 0.22 nm that corresponds to the (012) and (100) crystal planes of NiO , [78,79] and CoO, [80] respectively. For NMC 811 a similar trend was observed, however there are additional contributions after cycling, in particular at 855.6 eV which indicates the possible formation of some Ni 3 + species (NiOOH), [81] which is typically observed when Ni 2 + precursors are used as OER electrocatalysts.…”