Two‐Dimensional Arrays of Transition Metal Nitride Nanocrystals

Abstract

The synthesis of low‐dimensional transition metal nitride (TMN) nanomaterials is developing rapidly, as their fundamental properties, such as high electrical conductivity, lead to many important applications. However, TMN nanostructures synthesized by traditional strategies do not allow for maximum conductivity and accessibility of active sites simultaneously, which is a crucial factor for many applications in plasmonics, energy storage, sensing, and so on. Unique interconnected two‐dimensional (2D) arrays of few‐nanometer TMN nanocrystals not only having electronic conductivity in‐plane, but also allowing transport of ions and electrolyte through the porous nanosheets, which are obtained by topochemical synthesis on the surface of a salt template, are reported. As a demonstration of their application in a lithium–sulfur battery, it is shown that 2D arrays of several nitrides can achieve a high initial capacity of >1000 mAh g−1 at 0.2 C and only about 13% degradation over 1000 cycles at 1 C under a high areal sulfur loading (>5 mg cm−2).

Enhanced Rate Capability of Ion‐Accessible Ti3C2Tx‐NbN Hybrid Electrodes

“…2D arrays of NbN nanocrystals were synthesized using a salt‐templating method, as reported previously. [ 50 ] Briefly, the KCl salt powder coated with an Nb salt precursor was annealed in the ammonia atmosphere to obtain NbN@KCl. After removing the salt with deionized water, the 2D arrays of NbN nanocrystals are readily dispersed in water (inset of Figure 1).…”

Salt‐Assisted Synthesis of 2D Materials

“…[ 173 ] Xiao et al reported STM‐synthesized 2D arrays metal nitrides (CrN, TiN, and NbN) that demonstrated promising application in the Li‐S battery ( Figure ). [ 174 ] The unique interconnected structure of these materials with high conductivity allowed both fast ion and electron transport. The NbN‐based device achieves a high specific capacity of 1000 mAh g −1 as well as good stability even with a high areal sulfur loading over 5 mg cm −2 .…”

Interconnected Two‐dimensional Arrays of Niobium Nitride Nanocrystals as Stable Lithium Host

“…Considering the high electron conductivity of NbN‐based host, we assume the removal of current collector may be possible in the future, which could further improve the volumetric energy density of the cell. We have previously reported the use of similar NbN porous arrays in Li−S battery cathodes [32] . Combined with the results reported above, there is a possibility to design a Li−S battery with both electrodes utilizing NbN or other TMN arrays as frameworks for both, Li and S deposition.…”

“…In this work, we report on a stable Li‐metal anode composed of 2D arrays of NbN nanocrystals as a Li host. Combining advantages of both, zero‐dimensional (0D) and 2D morphologies, interconnected 2D arrays of few‐nanometer NbN nanocrystals were synthesized using a topochemical method in ammonia on a salt template, [32] providing both high metallic conductivity and abundant ion transport channels. With 10 % Ti 3 C 2 MXene as a conductive binder, which also helps improve the mechanical strength of the film, [33] a flexible freestanding NbN‐based host was fabricated followed by electrochemical Li deposition to precisely load and tune the Li amount, forming a Li‐metal anode.…”