Bimetallic Cobalt–Nickel Selenide Nanocubes Embedded in a Nitrogen-Doped Carbon Matrix as an Excellent Li-Ion Battery Anode

Abstract

Lithium-ion batteries (LIBs) have been widely used for portable electronics and electric vehicles; however, the low capacity in the graphite anode limits the improvement of energy density. Transition-metal selenides are promising anode material candidates due to their high theoretical capacity and controllable structure. In this study, we successfully synthesize a bimetallic transition-metal selenide nanocube composite, which is well embedded in a nitrogen-doped carbon matrix (denoted as CoNiSe2/NC). This material shows a high capacity and excellent cycling for Li-ion storage. Specifically, the reversible capacity approaches ∼1245 mA h g–1 at 0.1 A g–1. When cycled at 1 A g–1, the capacity still remains at 642.9 mA h g–1 even after 1000 cycles. In-operando XRD tests have been carried out to investigate the lithium storage mechanism. We discover that the outstanding performance is due to the unique CoNiSe2/NC nanocomposite characteristics, such as the synergistic effect of bimetallic selenide on lithium storage, the small particle size, and the stable and conductive carbon structure. Therefore, this morphology structure not only reduces the volume change of metal selenides but also produces more lithium storage active sites and shortens lithium diffusion paths, which results in high capacity, good rate, and long cycling.

Interconnected CoNi-Se Hollow Flakes through Reduced Graphene Oxide Sheets as a Cathode Material for Hybrid Supercapacitors

“…Moreover, the detection of a distinct peak at 59.2 eV signifies the presence of Se–O bonding structures. This observation suggests surface oxidation of selenium species to form more thermodynamically stable oxyhydroxides shell, likely occurring as a result of exposure to ambient conditions during the testing phase. − …”

MOF-Derived Bimetallic Selenide CoNiSe2 Nanododecahedrons Encapsulated in Porous Carbon Matrix as Advanced Anodes for Lithium-Ion Batteries

“…In Figure g, diffraction peaks were observed at 2θ values of 45.6, 50.8, and 52.6°, corresponding to the standard pattern of the window material Be (PDF no. 22-0111) . Peaks at 41.3 and 44.1° were assigned to BeO (PDF no.…”

Structural Engineering of SnSe Encapsulated in Nitrogen-Doped Carbon Nanotubes for High-Performance Lithium-Ion Battery Anodes

“…The Raman spectra measurement was carried out to analyze the carbon shell. From the Raman spectra of the SnSe@NCNT nanocomposite (Figure S3), it can be seen that the two characteristic peaks located at ∼1353 and 1586 cm –1 correspond to D and G bands of the carbon shell, which represent disordered and sp 2 -hybridized carbon, respectively . The I D / I G ratio of SnSe@NCNT is estimated to be 0.91, suggesting the low graphitization degree of the carbon shell, which could efficiently improve the electronic conductivity and facilitate charge transport.…”

“…Nowadays, owing to the overwhelming advantages of superior energy density, long cycling lifespan and environmental benignity, lithium-ion batteries (LIBs) are widely employed in portable electronics and electric vehicles. − Nevertheless, commercial graphite cannot satisfy the power supply demands of rapidly developed high-performance energy storage devices because of the low capacity. − Therefore, enormous efforts have been dedicated to designing and pursuing advanced alternatives with improved specific capacity, outstanding rate capability, and good long-life stability. In this regard, various carbonaceous materials, − alloy-based anodes, − and metal oxide/sulfide/selenide/phosphide anodes ,− have been explored. Among these materials, SnSe has drawn great attention as one potential candidate by virtue of the high theoretical capacity (847 mAh g –1 ), environmentally friendly nature, earth abundance, and cost effectiveness. − As a typical semiconductor material, SnSe is a layered transition metal chalcogenide with a distorted NaCl structure, which is maintained by van der Waals force between layers, facilitating lithium-ion insertion and extraction. , However, similar to other alloyed materials, the practical application of SnSe is largely hampered by the low intrinsic electrical conductivity and massive volume expansion during charge–discharge cycles, resulting in rapid capacity fading stemmed by unstable architecture and inferior rate capability induced by sluggish electrochemical reaction kinetics. − …”