Doping Induced Hierarchical Lattice Expansion of Cobalt Diselenide/Carbon Nanosheet Hybrid for Fast and Stable Sodium Storage

Electronic structure engineering on electrode materials could bring in a new mechanism to achieve high energy and high power densities in sodium ion batteries. Herein, we design and create Co vacancies at the interface of atomically thin CoSe2/graphene heterostructure and obtain Co1−xSe2/graphene heterostructure electrode materials that facilitate significant Na+ intercalation pseudocapacitance. Density functional theory (DFT) calculation suggests that the Na+ adsorption energy is dramatically increased, and the Na+ diffusion barrier is remarkably reduced due to the introduction of Co vacancy. The optimized electrode delivers a superior capacity of 673.6 mAh g−1 at 0.1 C, excellent rate capability of 576.5 mAh g−1 at 2.0 C and ultra‐long life up to 2000 cycles. Kinetics analysis indicates that the enhanced Na+ storage is mainly attributed to the intercalation pseudocapacitance induced by Co vacancies. This work suggests that the creation of cation vacancy could bestow heterostructured electrode materials with pseudocapacitive Na+ intercalation for high‐capacity and high‐rate energy storage.

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“…In anodic scans, only a strong oxidation peak appears at about 1.93 V, representing the desodiation process and the formation of CoSe 2 : [21]

true Co + 2 Na_{2} Se \to Na_{x} CoSe_{2} + (4 - x) Na^{+} + (4 - x) normale^{-} Na_{x} CoSe_{2} \to x Na^{+} + CoSe_{2} + x normale^{-}

…”

Section: Resultsmentioning

confidence: 99%

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

et al. 2021

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“…In anodic scans, only a strong oxidation peak appears at about 1.93 V, representing the desodiation process and the formation of CoSe 2 : [21]

true Co + 2 Na_{2} Se \to Na_{x} CoSe_{2} + (4 - x) Na^{+} + (4 - x) normale^{-} Na_{x} CoSe_{2} \to x Na^{+} + CoSe_{2} + x normale^{-}

…”

Section: Resultsmentioning

confidence: 99%

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

et al. 2021

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“…[10,11] Transition metal chalcogenides (TMCs) were considered as promising electrode materials for SIBs anode material because of their higher sodium storage capacity based on conversion reactions. [12,13] Therein, the bond of M─Se in TMCs is weaker than that in the metal oxides/ sulfides, so the metal selenide could store more sodium ions through the incident conversion reaction. [14] As an alternative to carbon anode, metal selenide could also improve the battery safety by reducing the risk of sodium dendrite formation in the low reaction voltage range.…”

Section: Introductionmentioning

confidence: 99%

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

Fan

Liu

et al. 2021

Energy Tech

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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.

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Doping Induced Hierarchical Lattice Expansion of Cobalt Diselenide/Carbon Nanosheet Hybrid for Fast and Stable Sodium Storage

Cited by 9 publications

References 32 publications

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

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

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Doping Induced Hierarchical Lattice Expansion of Cobalt Diselenide/Carbon Nanosheet Hybrid for Fast and Stable Sodium Storage

Cited by 9 publications

References 32 publications

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co1−xSe2/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co1−xSe2/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co1−xSe2/Graphene Heterostructure for Sodium‐Ion Batteries

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

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Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co_1−xSe₂/Graphene Heterostructure for Sodium‐Ion Batteries

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