In Situ Growth of CoSe₂ Coated in Porous Carbon Layers as Anode for Efficient Sodium‐Ion Batteries

Abstract

A novel composite material of CoSe2/N‐doped carbon box (CoSe2/NC) is successfully synthesized using zeolitic imidazolate frameworks‐67 as the sacrificial templates through a simple two‐step calcine process. The CoSe2 nanoparticles are encapsulated in N‐doped carbon layers, which can seriously avoid agglomeration. When used CoSe2/NC as anode materials for sodium‐ion batteries (SIBs), it exhibits an excellent high reversible specific capacity and a superior cycling stability of 390.2 mA h g−1 at 5 A g−1 over 4000 cycles. The excellent performance of CoSe2/NC can be attributed to cooperation of CoSe2 nanoparticles and N‐doped carbon layers. Carbon layers coated on the surface of CoSe2 nanoparticles not only improve a well conductivity to facilitate the charge transfer, but also buffer the structure to expand during the Na+ insertion/extraction process. Furthermore, this novel porous structure provides more active sites and increases contact areas between the materials and the electrolyte, thus increasing the specific capacity and cycle stability. This work provides a possibility of anode materials for SIBs with excellent electrochemistry performance.

Ingeniously Designed Yolk–Shell-Structured FeSe2@NDC Nanoboxes as an Excellent Long-Life and High-Rate Anode for Half/Full Na-Ion Batteries

“…The relatively high surface area and abundant mesopores effectively promote electrochemical kinetic behavior and optimize full infiltration of electrolytes, thus improving the electrochemical performance of the target sample. 33 The surface electronic state and chemical composition of FeSe 2 @NDC NBs are recorded by XPS. The full survey spectrum manifests that C, N, Se, and Fe are all present in the FeSe 2 @NDC NBs (Figure S6), which is in line with TEM− EDS mapping results.…”

“…As shown in Figure f, the pore sizes of FeSe 2 @NDC NBs mainly exhibit the mesopore structure in the range of 2–15 nm, while P-FeSe 2 shows extremely low porosity. The relatively high surface area and abundant mesopores effectively promote electrochemical kinetic behavior and optimize full infiltration of electrolytes, thus improving the electrochemical performance of the target sample …”

Metal–organic framework-derived nitrogen-doped carbon-confined CoSe2 anchored on multiwalled carbon nanotube networks as an anode for high-rate sodium-ion batteries

“…A similar phenomenon was also reported in other CoSe 2 -based materials. 29,[45][46][47] Then, the Raman spectra were collected to confirm the presence of N-doped carbon and MWCNTs in the CoSe 2 hybrids. As Fig.…”

“…Li et al reported CoSe 2 /N-doped carbon box from the sacrificial ZIF-67 templates, which shows excellent cycling performance (390.2 mA h g −1 at a current density of 5 A g −1 for 4000 cycles). 45 Kang et al constructed necklace-like CNT/CoSe 2 @NC composites using ZIF-67 as the precursors, which exhibit a very high reversible capacity of 404 mA h g −1 at 200 mA g −1 over 120 cycles. 31 Despite this, it is urgently needed to obtain CoSe 2 -based anodes with high performance for practical applications.…”

Architectural design of anode materials for superior alkali-ion (Li/Na/K) batteries storage

“…Whereas compared with that of Li + (0.76 Å, and molar mass 6.94 g mol −1 ), the larger ionic radius (Na + = 1.02 Å, and K + = 1.38 Å) and the heavier atomic weights (Na + = 22.99 g mol −1 , K + = 39.10 g mol −1 ) of Na + /K + lead to lots of trouble including higher diffusion barriers 27 – 29 . On the other hand, the larger ionic radius causes sluggish kinetics 30 , 31 , large volume change during insertion/extraction processes within the existing electrode materials 32 , 33 , poor cycling stability 34 – 37 , and short cycle life 38 – 40 . Hence, identifying an appropriate electrode material capable of hosting various alkali ions poses a significant challenge due to the expanding ionic radius and distinct interactions with the host electrodes 41 , 42 .…”