In‐Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium‐Ion Batteries

Wu, Renbing; Wang, Danping; Rui, Xianhong; Liu, Bo; Zhou, Kun; Law, Adrian Wing‐Keung; Yan, Qingyu; Wei, Jun; Chen, Zhong

doi:10.1002/adma.201500783

Cited by 630 publications

(326 citation statements)

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“…1f). Although it is ideal to achieve phase pure cobalt sulfide materials via control over the sulfurization temperature, it is actually difficult to achieve this using the proposed experimental procedure, which is consistent with the recent reports, 45,46 where the authors used sulfur for the sulfurization of ZIF-67 under different temperatures and the formation of the assynthesized composites is complicated during the sulfurization and carbonization procedure. The XRD results clearly showed that with the increase of sulfurization temperatures, the XRD peaks for cobalt sulfide (mainly Co 1-x S phase) became more intense and sharper, accompanied with the appearing of Co 3 S 4 , indicating the growth of crystallites and crystallinity improvement of cobalt sulfide.…”

Section: Resultssupporting

confidence: 82%

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

et al. 2015

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Exploring highly-efficient and low-cost bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reactions (OER) in the renewable energy area has gained its momentum but still remains a significant challenge. Here we represent a simple but efficient way that utilizes ZIF-67 as the precursor and template for the one-step generation of homogeneous dispersed cobalt sulfide/N,S-codoped porous carbon nanocomposites as high-performance electrocatalysts. Due to the favourable molecular-like structural features and uniform dispersed active sites in the precursor, the resulting nanocomposites featured with unique core-shell structure, high porosity, homogeneous dispersion active components together with N and S-doping effect, not only show excellent electrocatalytic activity towards ORR with the high onset potential (around -0.04 V vs -0.02 V for benchmark Pt/C catalyst) and four-electron pathway, and OER with a small overpotential of 0.47 V for 10 mA cm −2 current density, but also exhibit superior stability (92%) to commercial Pt/C catalyst (74%) in ORR and promising OER stability (80%) with good methanol tolerance. Our findings suggest that the transition metal sulfide-porous carbon nanocomposites derived from the one-step simultaneously sulfurization and carbonization of zeolitic imidazolate frameworks are excellent alternative bifuncitonal electrocatalysts towards ORR and OER in the next generation of energy storage and conversion technologies.With the depletion of hydrocarbon-based energy resources and the increasing global energy demands, it is imperative to develop green and sustainable energy storage and conversion technologies as alternatives to currently widely used fossil fuels. 1-3 Electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play key roles in several important next-generation energy storage and conversion technologies, such as fuel cells, metal-air batteries and water splitting. [4][5][6][7][8][9][10][11][12][13] Hitherto, most efficient electrocatalysts for ORR/OER contain precious metals including Pt or Ir; however, due to the prohibitive cost, poor stability of precious metals, the sluggish kinetics for ORR and the large polarisation, it is highly desirable to discover highly efficient and low-cost earthabundant non-precious electroactive materials that can rival the performances of precious metal-based catalysts. 14-17Many efforts have, therefore, been devoted to transition metal oxides/sulfides based materials, as many transition metals like cobalt, manganese have been widely considered to be electrochemical active for ORR and OER. Particularly, cobalt sulfides (Co x S y ) with different phases have been previously investigated as ORR and OER electrode catalysts and exhibited attractive electrocatalytic performance among different nonprecious and late transition metal chalcogenides.18 Co 9 S 8 is a good catalyst for ORR. 21 However, the complicated preparation procedures coupled with the low electrical conductivities of cobalt s...

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Section: Resultssupporting

confidence: 82%

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

et al. 2015

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“…According to the literature we reviewed, the mixed phase of cobalt sulfide is easily obtained during the preparation28, 29, 30, 31 and can be purified by subsequent annealing in air 32. Wu et al obtained a mixed phase of CoS and Co 9 S 8 by mixing ZIF‐67 with sulfur powder and annealing in an argon atmosphere 6. We find two reasons why carbon‐coated cobalt sulfide materials form a mixture phase through our experiments.…”

Section: Resultsmentioning

confidence: 65%

“…Recently, transition‐metal chalcogenides (TMCs) have attracted tremendous attention for its multitude of possible valence states, stoichiometric compositions, and crystal structure 4, 5, 6, 7. Compared with their oxide counterparts, TMCs usually exhibit better electrical conductivity, and thermal and mechanical stability 7.…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of CoS_x Nanocrystals into N/S Co‐Doped Honeycomb‐Like 3D Porous Carbon for High‐Performance Lithium Storage

et al. 2018

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A honeycomb‐like 3D N/S co‐doped porous carbon‐coated cobalt sulfide (CoS, Co9S8, and Co1– xS) composite (CS@PC) is successfully prepared using polyacrylonitrile (PAN) as the nitrogen‐containing carbon source through a facile solvothermal method and subsequent in situ conversion. As an anode for lithium‐ion batteries (LIBs), the CS@PC composite exhibits excellent electrochemical performance, including high reversible capacity, good rate capability, and cyclic stability. The composite electrode delivers specific capacities of 781.2 and 466.0 mAh g−1 at 0.1 and 5 A g−1, respectively. When cycled at a current density of 1 A g−1, it displays a high reversible capacity of 717.0 mAh g−1 after 500 cycles. The ability to provide this level of performance is attributed to the unique 3D multi‐level porous architecture with large electrode–electrolyte contact area, bicontinuous electron/ion transport pathways, and attractive structure stability. Such micro‐/nanoscale design and engineering strategies may also be used to explore other nanocomposites to boost their energy storage performance.

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“…For Ni-LVO, the increase in capacity during cycling was also commonly observed for metal oxides and may be attributed to the improved lithium diffusion kinetics by the gradual activation process and reversible reaction between materials and electrolytes. [36][37][38] For the LVO electrode, the discharge capacity decreased to 47% compared with the initial value. The coulombic efficiency of both LVO and Ni-LVO electrodes remained constant close to 100%.…”

Section: Resultsmentioning

confidence: 99%

“…The extra capacity at low potential may be related to the decomposition of the electrolyte upon reduction with the formation of a gel-like polymeric film 31 and interfacial storage, 32,33 which has also been observed in other anode materials such as SnO 2 , 34 CoO 35 and CoS x . 36 The capacity of the LVO electrode decreased rapidly at 50 mA g − 1 . The Ni-LVO electrode exhibited higher capacity than the bare LVO electrode.…”

Section: Resultsmentioning

confidence: 99%

Effects of high surface energy on lithium-ion intercalation properties of Ni-doped Li3VO4

et al. 2016

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Nickel was doped into Li 3 VO 4 (Ni-LVO) successfully via a facile room temperature reaction, and the resulting Ni-LVO nanocrystallites showed excellent lithium-ion storage properties with a capacity of 650 mAh g − 1 at 50 mAh g − 1 and excellent capacity stability as an anode in lithium-ion batteries, maintaining nearly 100% of the initial reversible capacity after 800 cycles at 1 A g − 1 . The superior electrochemical properties arose largely from the nickel doping in the Ni-LVO. The surface energy of the electrode material was analyzed by an inverse gas chromatography method, and the Ni-LVO surface energy, 43.91 mJ m − 2 , was much higher than the 30.74 mJ m − 2 of Li 3 VO 4 . X-ray photoelectron spectra results demonstrated that nickel doping promoted the formation of tetravalent vanadium ions, V 4+ , as well as a more amorphous surface of Li 3 VO 4 , thus probably resulting in more nucleation sites for the phase transformation and reduced activation energy of the redox reactions and phase transition during the lithium-ion intercalation/extraction processes. NPG Asia Materials (2016) 8, e287; doi:10.1038/am.2016.95; published online 22 July 2016 INTRODUCTION Li 3 VO 4 (LVO), whose structure consists of corner-sharing VO 4 and LiO 4 tetrahedra, has been studied as a promising anode material for lithium-ion batteries. 1,2 It possesses several advantages over other anode materials. First, LVO has a small structural and volume change during lithiation/delithiation processes, thus resulting in good cyclic durability. 3 Second, it has high ionic conductivity (~10 − 4 S cm − 1 ), which facilitates the effective diffusion of lithium ions in bulk. 4 Third, compared with Li 4 Ti 5 O 12 , LVO can intercalate lithium ions in a low-voltage region (between 0.5 and 1.0 V vs Li/Li + ), thus eventually offering a high full cell energy density and maintaining good safety. 3,5 Finally, the hollow, lantern-like, three-dimensional structure of LVO crystal provides many empty sites to accommodate lithium ions and serves as lithium ion insertion channels. Theoretical calculations indicate that the inserted lithium ions have two different Wyckoff sites, which are stably occupied by three external lithium ions corresponding to a theoretical capacity of 591 mAh g − 1 when discharged to 0.01 V vs Li/Li + . 6 Despite these advantages, LVO suffers from low electrical conductivity, which may cause large polarization and poor rate capability. Hybridization with carbon materials such as graphite, 7,8 carbon nanotubes 9 and graphene 10,11 and reduction of the LVO particle size have been proven to be effective ways to enhance electrical conductivity and abate polarization. For example, carbon-encapsulated LVO nanoparticles synthesized by a simple solid-state method exhibit excellent rate capability and long cycling performance. 1 In addition, defects introduced by doping, thermal treatment at an inert or

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In‐Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium‐Ion Batteries

Cited by 630 publications

References 35 publications

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

Encapsulation of CoS_x Nanocrystals into N/S Co‐Doped Honeycomb‐Like 3D Porous Carbon for High‐Performance Lithium Storage

Effects of high surface energy on lithium-ion intercalation properties of Ni-doped Li3VO4

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In‐Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium‐Ion Batteries

Cited by 630 publications

References 35 publications

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

Cobalt sulfide/N,S codoped porous carbon core–shell nanocomposites as superior bifunctional electrocatalysts for oxygen reduction and evolution reactions

Encapsulation of CoSx Nanocrystals into N/S Co‐Doped Honeycomb‐Like 3D Porous Carbon for High‐Performance Lithium Storage

Effects of high surface energy on lithium-ion intercalation properties of Ni-doped Li3VO4

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Encapsulation of CoS_x Nanocrystals into N/S Co‐Doped Honeycomb‐Like 3D Porous Carbon for High‐Performance Lithium Storage