Nitrogen‐Doped Hard Carbon on Nickel Foam as Free‐Standing Anodes for High‐Performance Sodium‐Ion Batteries

Abstract

Nitrogen‐doped hard carbon on Ni foam (NC/NF) with numerous active sites, expanded interlayer distance (0.49 nm), and highly ordered pseudo‐graphic structure is synthesized by a melamine‐assisted hydrothermal pretreatment and subsequent pyrolysis procedure. The high content configurations of pyrrolic‐nitrogen and pyridinic‐nitrogen in NC/NF could provide abundant active sites and defects for efficient Na+ adsorption/desorption and improved transport kinetics. The obvious flocculent structures on carbon surface, corresponding to the highly ordered pseudo‐graphic structure, could enhance the transport kinetics for electrons. The strong electrostatic repulsion of pyrrolic‐nitrogen could expand interlayer distance, facilitating Na+ insertion/extraction process. The balance between high nitrogen content and sufficient graphitization degree comes into strong carbon frameworks with enhanced structural stability and electronic conductivity. When served as free‐standing anodes for sodium‐ion batteries (SIBs), NC/NF presents high rate capability of 128.5 mAh g−1 at 10 A g−1, and excellent cycling stability of 225.4 mAh g−1 after 1000 cycles under high current density of 5 A g−1. These results demonstrate a new light to prepare advanced anodes for SIBs.

Intercalation pseudocapacitance in 2D N-doped V2O3 nanosheets for stable and ultrafast lithium-ion storage

“…36,37 Contrast of the initial and subsequent discharge profiles indicated the irreversible capacity loss of the N-V 2 O 3 , N-VO 0.9 and VN electrodes, associated with the formation of the SEI layer and the decomposition process on the surface of oxides and nitrides. [37][38][39] It is observed that the charge-discharge curves of the N-V 2 O 3 electrode display gently slope shapes, in accordance with its CV curves and further revealing the capacitive storage behavior. In the following cycles, the charge-discharge profiles are almost overlapped at different current densities, further confirming that the N-V 2 O 3 , N-VO 0.9 and VN electrodes exhibit cycling stability and Li + -storage reversibility (Fig.…”

“…3d–f deliver the sloping voltage profiles with no obvious plateaus between 0.01 and 3.0 V. Additionally, the sloped region corresponds to the Li + adsorption storage in a wide range at a high potential and the plateau region corresponds to embedded storage lithium at a lower potential, which are corresponding to the weak dumps of the CV curves. 36,37 Contrast of the initial and subsequent discharge profiles indicated the irreversible capacity loss of the N-V 2 O 3 , N-VO 0.9 and VN electrodes, associated with the formation of the SEI layer and the decomposition process on the surface of oxides and nitrides. 37–39 It is observed that the charge–discharge curves of the N-V 2 O 3 electrode display gently slope shapes, in accordance with its CV curves and further revealing the capacitive storage behavior.…”

Recent Progress in Hard Carbon Anodes for Sodium‐Ion Batteries

“…In addition, researchers have found that the local graphite microcrystalline structure can be regulated by introducing metal ions and heteroatoms (N, C, etc. ), [59][60][61] which can effectively improve electron transport and ions diffusion during electrochemical reactions. As shown in Figure 3a, Wu et al [62] doped natural K þ into hard carbon, resulting in the (002) diffraction peak shifting to lower angle of in-XRD (Figure 3c), which effectively enlarged the interlayer spacing (0.4 nm) and improved the cycle performance of the battery (Figure 3b).…”

Plasma-activated tight and uniform grown of metal-organic frame-work on carbon cloth for stable Li metal anode

“…Both pyrrolic and pyridinic N, with their extra pair of electrons, exhibit high chemical reactivity as electron-rich donors, facilitating the de-solvation process of lithium ions. 24,44,45 Conversely, graphitic nitrogen is unreactive with lithium ions due to its provision of two single electrons in two orbitals. 45 Lithium symmetric cell analysis.…”