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Cobalt telluride anchored to nitrogen-rich carbon dodecahedra (CoTe@NCD) was synthesized by simultaneous pyrolysis-tellurium melt impregnation of ZIF-67 MOFs. The purely thermal method involved no secondary chemicals and no waste byproducts. The result is a microstructure consisting of nanoscale 86 wt% CoTe intermetallic nanoparticles contained within a thin N-rich carbon matrix. During electrochemical cycling, the 21 nm average diameter CoTe provides short diffusion paths for Na + /K + ions, which in conjunction with the electrically conducting carbon matrix allow for rapid potassiation or sodiation. As potassium ion battery (PIB and KIB) and sodium ion battery (NIB and SIB) anodes, CoTe@NCD demonstrates attractive reversible capacity, promising cycling stability, and state-of-the-art rate performance. For example, as a KIB anode, the CoTe@NCD electrode exhibits a reversible capacity of 380 mA h g −1 at 50 mA g −1 and a fast charge capacity of 136 mA h g −1 at 1000 mA g −1 . As a NIB anode, it also displays excellent rate capability achieving 620 mA h g −1 at 50 mA g −1 and 345 mA h g −1 at 1000 mA g −1 . 

We synthesized Co 2 P nanoparticle encapsulated N-doped carbon nanocages through one-step carbonization–phosphidation of ZIF-67. As potassium ion battery (KIB, PIB) anodes, the Co 2 P@NCCs display state-of-the-art electrochemical performance, including the most favorable fast charge characteristics reported. The single-nanometer thick carbon cage yields rapid solid-state K-ion diffusion and prevents aggregation/pulverization of 40 nm cobalt phosphide. 

The lithium-sulfur (Li-S) redox battery system is considered to be the most promising next-generation energy storage technology due to its high theoretical specific capacity (1673 mAh g−1), high energy density (2600 Wh kg−1), low cost, and the environmentally friendly nature of sulfur. Though this system is deemed to be the next-generation energy storage device for portable electronics and electric vehicles, its poor cycle life, low coulombic efficiency and low rate capability limit it from practical applications. These performance barriers were linked to several issues like polysulfide (LiPS) shuttle, inherent low conductivity of charge/discharge end products, and poor redox kinetics. Here, we review the recent developments made to alleviate these problems through an electrocatalysis approach, which is considered to be an effective strategy not only to trap the LiPS but also to accelerate their conversion reactions kinetics. Herein, the influence of different chemical interactions between the LiPS and the catalyst surfaces and their effect on the conversion of liquid LiPS to solid end products are reviewed. Finally, we also discussed the challenges and perspectives for designing cathode architectures to enable high sulfur loading along with the capability to rapidly convert the LiPS.