Mechanically Resilient Graphene Assembly Microspheres with Interlocked N‐Doped Graphene Nanostructures Grown In Situ for Highly Stable Lithium Metal Anodes

Abstract

Li metal is considered the most attractive anode material for high‐energy Li batteries. However, the uncontrollable growth of Li dendrites and severe volume changes during Li plating and stripping inhibit the practical application of Li metal anodes. Herein, a synergistic strategy is developed not only to suppress Li dendrite growth but also to withstand repeated volume changes during long‐term cycling. Specifically, mechanically resilient graphene assembly microspheres with interlocked Ni/N‐doped lithiophilic graphene nanostructures grown in situ are developed as stable 3D graphene hosts for Li‐metal anodes. Importantly, the approach provides a novel strategy to control radial distribution of lithiophilic Ni nanocatalysts in the graphene assembly. These 3D graphene hosts can repeatedly guide the uniform deposition of Li owing to the high lithiophilicity of Ni nanocatalysts and the N‐doped graphene nanostructures. Furthermore, graphene nanoshell forms in situ between the graphene layers in the inner part of the graphene assembly, creating strong contacts between rGO layers and providing the 3D graphene host with high structural integrity. Notably, the approach emphasizes mechanical resilience of the 3D graphene host, which retains its initial morphology after repeated Li plating/stripping cycles. Consequently, the 3D graphene host maintains a highly stable coulombic efficiency of 99% over 500 cycles.

Spatially Confined Fe7S8 Nanoparticles Anchored on a Porous Nitrogen-Doped Carbon Nanosheet Skeleton for High-Rate and Durable Sodium Storage

“…It is noted that all of these vibration peaks have become much weaker in intensity in the Fe 7 S 8 /NC-25 sample, which is probably due to the influence of sulfurization treatment on these functional groups. Different from the pristine CNs, an exclusive C−N bending vibration peak appears at about 1420 cm −1 in the Fe 7 S 8 /NC-25 sample, 40,42 indicating the successful N doping in the CNs during the sulfurization process through the decomposition of TAA. To further perform the composition analysis of Fe 7 S 8 /NC-25, TG measurement was carried out in air.…”

“…39 Moreover, the FTIR spectra of the pristine CNs and Fe 7 S 8 /NC-25 samples were recorded for the analyses of functional groups on the CNs. As shown in Figure 1G, the pristine CNs exhibit four obvious bands centered at about 3440, 2920, 1650, and 1380 cm −1 , which are related to the O−H stretching vibration, C−H asymmetric stretching vibration, C�O stretching vibration, and O−H bending vibration, respectively, 40,41 suggesting the presence of rich oxygen-containing groups, which play a key role for the efficient metal chelating reaction of CNs with Fe 3+ .…”

Stable Plating and Stripping of Lithium Metal Anodes through Space Confinement and Stress Regulation

“…Typically, the D/G ratio (I D /I G ) represents the graphitic degree. 46,58 N-rGO, VC-rGO, and W-rGO showed a lower I D /I G (1.40, 1.38, and 1.45) than that of GO (1.58) since the defects associated with oxygen groups were removed from the graphene layers after reduction. The I D /I G of N-rGO (1.40) is relatively higher than that of VC-rGO (1.38), which might be the result that C−N bonds were introduced into graphene sheets after the reduction process involving hydrazine hydrate, as well as numerous new sp 2 domains in smaller size with more edge defects created upon a higher degree of reduction.…”

“…In the Raman spectra of different rGOs, all samples show two prominent peaks: D (1350 cm –1 ) and G (1580 cm –1 ) (Figure S12). Typically, the D/G ratio ( I D / I G ) represents the graphitic degree. , N-rGO, VC-rGO, and W-rGO showed a lower I D / I G (1.40, 1.38, and 1.45) than that of GO (1.58) since the defects associated with oxygen groups were removed from the graphene layers after reduction. The I D / I G of N-rGO (1.40) is relatively higher than that of VC-rGO (1.38), which might be the result that C–N bonds were introduced into graphene sheets after the reduction process involving hydrazine hydrate, as well as numerous new sp 2 domains in smaller size with more edge defects created upon a higher degree of reduction. , Both morphological observation and spectral analysis show that hydrazine hydrate reduces GO properly through the precise removal of oxygen groups and the ensuing doping of cationic nitrogen dopants, resulting in small and few-layered graphene nanosheet self-assembling into a cellular structure.…”

3D-hosted lithium metal anodes

“…46 Other related scaffolds/hosts also exhibited small volume change values (o10%). [47][48][49][50][51][52][53][54][55][56] For the scaffold/host strategy, based on the success of mitigation of volume change, researchers simultaneously started to focus on the mechanisms behind the scaffold/host working to inhibit Li dendrite growth. Before delving into these mechanisms, it is important to understand how Li dendrites form.…”