Rambutan‐like hollow carbon spheres decorated with vacancy‐rich nickel oxide for energy conversion and storage

Abstract

Transition metal oxides hold great promise for lithium‐ion batteries (LIBs) and electrocatalytic water splitting because of their high abundance and high energy density. However, designing and fabrication of efficient, stable, high power density electrode materials are challenging. Herein, we report rambutan‐like hollow carbon spheres formed by carbon nanosheet decorated with nickel oxide (NiO) rich in metal vacancies (denoted as h‐NiO/C) as a bifunctional electrode material for LIBs and electrocatalytic oxygen evolution reaction (OER). When being used as the anode of LIBs, the h‐NiO/C electrode shows a large initial capacity of 885 mA h g−1, a robust stability with a high capacity of 817 mA h g−1 after 400 cycles, and great rate capability with a high reversible capacity of 523 mA h g−1 at 10 A g−1 after 600 cycles. Moreover, working as an OER electrocatalyst, the h‐NiO/C electrode shows a small overpotential of 260 mV at 10 mA cm−2, a Tafel slope of 37.6 mV dec−1 along with good stability. Our work offers a cost‐effective method for the fabrication of efficient electrode for LIBs and OER.

Highly Porous NiCoSe4 Microspheres as High‐Performance Anode Materials for Sodium‐Ion Batteries

“…The CV curves of NiCoSe 4 @NC@rGO electrode exhibit a much enhanced overlapping than NiCoSe 4 @NC in the subsequent 2–3 cycles, indicating improved reversibility by rGO wrapping . In Figure b and Figure S7b, three discharge plateaus are clearly observed at 1.43, 1.1 and 0.78 V, in agreement with the CV measurements …”

Direct growth of ordered N‐doped carbon nanotube arrays on carbon fiber cloth as a free‐standing and binder‐free air electrode for flexible quasi‐solid‐state rechargeable Zn‐Air batteries

“…As shown in Figure S1E, the sharp nitrogen uptake at a low relative pressure region (p/p 0 < 0.1) and the obvious hysteresis at a moderate relative pressure region (p/ p 0 > 0.45) implies the existence of micropore and mesopore, respectively. 31,32 The pore size distribution of CC-A was calculated by Barrett-Joyner-Halenda equation from adsorption curve, showing the overall pore size of smaller than 10 nm and average pore size of about 2.2 nm ( Figure S1F). The pore volume was calculated to be 0.13 cm 3 /g.…”

Two‐Dimensional NiO@C‐N Nanosheets Composite as a Superior Low‐Temperature Anode Material for Advanced Lithium‐/Sodium‐Ion Batteries

“…Additionally, the severe aggregation and large volume changes between NiO nanoparticles (NPs) during Li-/Na-ion insertion/ extraction processes would further accelerate the capacity attenuation. [14,16,17] To address these issues, on the one hand, coating NiO NPs with chemically flexible and highly conductive carbon-based materials doped with heteroatoms, especially Ndoped carbonaceous composites; [18][19][20][21] on the other hand, designing unique nanostructures such as hollow microspheres, [22] nanosheets, [9] nanorods, [15] nanofibers, [23] nanotubes, [24] nanospheres, [25] nanoflakes, [26] nanoflowers, [27] can effectively shorten the ion/electron transport paths, and improve the contact interface at the electrolyte-electrodes. Although many reported NiO nanocomposites show superior Li-/Na-storage properties, their LT Li-/Na-storage performances have not yet been studied.…”