Recently, Prof. Chuncheng Yang and Prof. Qing Jiang reported a hybrid material of ultra-small Sb nanoparticles encapsulated in unique N-doped carbon nanonecklace (Sb/N-CNN). As an anode material in sodium-ion batteries (SIBs), the as-fabricated Sb/N-CNN exhibits superior rate property and cycling stability. The strategy proposed in this work may open an avenue to rationally develop high-performance anode materials for applications in advanced energy-storage devices.

Picture from Matter, 2019, 1: 720-733.

SIBs are emerging as a potential alternative to lithium-ion batteries, especially for large-scale applications, owing to abundant reserve, low cost and environmental benignity of sodium resources. However, a shortage of suitable anode materials with high capacity and superior cycling stability has become the major challenge for their future developments. Metallic Sb has been considered as a promising anode material in SIBs due to its high theoretical capacity (660 mAh g^-1) and low reaction potential (0.4-0.8 V versus Na⁺/Na). However, the large volumetric change (about 390%) during charging/discharging leads to a sharp decay of its capacity. In this work, a unique hybrid material of Sb/N-CNN was synthesized for the first time by using electrospinning and in situ substitution. Such a necklace-like structure has the following merits: (1) the island-like ultra-small Sb nanoparticles are well dispersed in the metal-organic framework (MOF)-derived carbon nanocages, effectively preventing their self-agglomeration; (2) the carbon nanocages are connected one by one, fabricated via electrospinning, enhancing the stability and conductivity of the electrodes; and (3) the N-doped porous carbon nanofibers and nanocages improve the wettability of the electrolyte and also provide efficient electrolyte diffusion paths and more active sites for Na⁺ insertion/extraction. As a consequence, the Sb/N-CNN exhibits excellent rate performance (314 mAh g^-1 at 20 A g^-1) and superior long-term cycling stability (401 mAh g^-1 after 6000 cycles at 1 A g^-1) as an anode material in SIBs.

This work has been published as an article in Matter, 2019, 1: 720-733. This project is financially supported by the National Natural Science Foundation of China, the Natural Science Foundation of Jilin Province, the Program for JLU Science and Technology Innovative Research Team, and the Fundamental Research Funds for the Central Universities.

Link: https://www.sciencedirect.com/science/article/pii/S2590238519300141