Fabrication of 2D NiO Porous Nanosheets with Superior Lithium Storage Performance via a Facile Thermal-Decomposition Method

Abstract

Because of their good mechanical flexibility and large exposed surfaces, two-dimensional (2D) nanostructures have attracted tremendous attention in the fields of renewable energy storage and conversion devices. However, fabricating 2D nanostructures with a facile and low-cost route remains a big challenge. In this work, a very facile thermal-decomposition strategy is proposed for preparing 2D NiO porous nanosheets by using nickel chloride and glucose as raw materials. In contrast to the microsized NiO polyhedrons, the 2D NiO porous nanosheets show significantly improved lithium storage capability. Benefiting from the robust 2D framework and porous nanostructure, the 2D NiO porous nanosheets exhibit high reversible capacity (926.5 mA h g–1 after 500 cycles at 1 A g–1), long cycling stability (557.7 mA h g–1 after 1100 cycles at 3 A g–1), and high-rate capability (350.7 mA h g–1 at 10 A g–1). The lithium storage mechanism of the 2D NiO porous nanosheets is explored based on ex situ X-ray diffraction, fourier transformation infrared spectrometry, transmission electron microscopy, and X-ray photoelectron spectroscopy measurements, combined with cyclic voltammetry and electrochemical impedance spectroscopy measurements. It reveals that the capacitive-controlled lithium storage originating from the reversible formation/dissolution of polymer/gel-like layer gives a remarkable contribution to the overall capacity of the 2D NiO porous nanosheets, which leads to the outstanding lithium storage performance. The 2D NiO porous nanosheets also show a good cycling performance when used as an anode material for full-cell lithium-ion battery (NiO//LiCoO2). The reported facile and low-cost method provides an avenue for the design and massive production of 2D nanostructured electrode materials for high performance lithium-ion batteries.

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

“…[14,41] The reduction peaks transform to about 0.86 V with a flat peak around 1.32 V for the succedent cycles, indicating the structural/textural modification after the first lithiation/delithiation processes. [9,15,19] The CV curves almost overlap in the subsequent cycles, indicating that the working electrode has excellent cycling stability. Figure 2b displays the galvanostatic charge and discharge (GCD) curves NiO@CÀ N NSs at 0.05 A g À 1 at different temperatures in LIBs.…”

“…The EIS spectra consists of two partly conterminal semicircles at between high/ medium frequencies and a straight sloping line at lowfrequency regions. [9,31] Sometimes, the low-frequency limit used for measurement may be too high to allow Li + to diffuse in the solid, so there may be a lack of sloped straight lines at low frequencies (Figure 4f). [43] Taking the EIS data at RT as an example (Figure 4a), R e of the battery reflects the combined of among separator, electrolyte and electrodes.…”

“…In recent years, two-dimensional (2D) transition metal oxides (TMOs) have boomed because of their large surface area, good mechanical flexibility, abundant active sites, and short ion diffusion transport paths, [9,10] 2D TMOs are deemed to be promising electrode materials of LIBs/SIBs. [11][12][13] Among these TMOs, NiO is a potential LT candidate due to its high theoretical specific capacity (C s , 718 mA h g À 1 ) and high crystal density of 6.67 g cm À 3 , suitable reversible potential, inexpensive, environmental friendliness.…”

“…[11][12][13] Among these TMOs, NiO is a potential LT candidate due to its high theoretical specific capacity (C s , 718 mA h g À 1 ) and high crystal density of 6.67 g cm À 3 , suitable reversible potential, inexpensive, environmental friendliness. [9,14,15] Unfortunately, NiO has poor Li-/Nastorage performances and inferior cycle performance under LT due to its low conductivity and sluggish electrode kinetics. 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.…”

“…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.…”