Superior lithium-storage properties derived from a high pseudocapacitance behavior for a peony-like holey Co 3 O 4 anode

et al. 2019

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Antimony is a competitive and promising anode material for sodium‐ion batteries (SIBs) due to its high theoretical capacity. However, the poor rate capability and fast capacity fading greatly restrict its practical application. To address the above issues, a facile and eco‐friendly sacrificial template method is developed to synthesize hollow Sb nanoparticles impregnated in open carbon boxes (Sb HPs@OCB). The as‐obtained Sb HPs@OCB composite exhibits excellent sodium storage properties even when operated at an elevated temperature of 50 °C, delivering a robust rate capability of 345 mAh g−1 at 16 A g−1 and rendering an outstanding reversible capacity of 187 mAh g−1 at a high rate of 10 A g−1 after 300 cycles. Such superior electrochemical performance of the Sb HPs@OCB can be attributed to the comprehensive characteristics of improved kinetics derived from hollow Sb nanoparticles impregnated into 2D carbon nanowalls, the existence of robust SbOC bond, and enhanced pseudocapacitive behavior. All those factors enable Sb HPs@OCB great potential and distinct merit for large‐scale energy storage of SIBs.

Section: Methodsmentioning

confidence: 95%

Ultrahigh Rate Performance of Hollow Antimony Nanoparticles Impregnated in Open Carbon Boxes for Sodium‐Ion Battery under Elevated Temperature

Xia

et al. 2019

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“…11,12 To solve these problems, two commonly utilized measures have been used to promote the performance of Co 3 O 4 -based nanocomposites. 13 One is combining Co 3 O 4 with carbonbased materials to form Co 3 O 4 /carbon composite, which can greatly enhance rate capability and conductivity. Simultaneously, the encapsulation of carbon-based materials can slightly relieve the volume change and maintain the mechanical stability of Co 3 O 4 .…”

Section: Introductionmentioning

confidence: 99%

“…However, like other TMOs materials, Co 3 O 4 suffers from two major defects. The first defect is the severe volume expansion/contraction during the repeated charging/discharging, leading to pulverization of the material and poor cycle stability. − The second defect is the inferior electronic conductivity of Co 3 O 4 , leading to poor rate performance. , To solve these problems, two commonly utilized measures have been used to promote the performance of Co 3 O 4 -based nanocomposites . One is combining Co 3 O 4 with carbon-based materials to form Co 3 O 4 /carbon composite, which can greatly enhance rate capability and conductivity.…”

Section: Introductionmentioning

confidence: 99%

Space-Confined Synthesis of Yolk–Shell Structured Co₃O₄/Nitrogen-Doped Carbon Nanocomposites with Hollow Mesoporous Carbon Nanocages as Advanced Functional Anodes for Lithium-Ion Batteries

Lü

Liu

ACS Appl. Energy Mater.

et al. 2020

Despite the high theoretical capacity as the anode material of lithium-ion batteries (LIBs), Co 3 O 4 is subjected to rapid capacity decline and poor rate performance owing to its severe volume expansion and poor electronic conductivity. Herein, a yolk− shell structured Co 3 O 4 nanocomposite with double carbon shells (Co 3 O 4 @NC@CNC) was fabricated as an electrode material to improve the properties of LIBs. The Co 3 O 4 @ NC@CNC was derived from ZIF-67 within carbon nanocages (CNC) by carbonization. The hollow CNC acted as nanoreactors, which could effectively control the growth of ZIF-67 within the CNC and reduce the particle size of Co 3 O 4 @nitrogen-doped carbon (Co 3 O 4 @NC) nanocomposite derived from ZIF-67. When assessed as an LIBs anode material, the optimized Co 3 O 4 @NC@CNC material exhibited outstanding properties with high capacity, superior cycling stability, and rate performance (960 mAh g −1 at 0.5 A g −1 and 772 mAh g −1 at 2 A g −1 after 100 cycles). The electrochemical properties were ascribed to the yolk−shell structure and the synergistic effect of the nanoscale Co 3 O 4 @NC and CNC, which improved the electronic conductivity, alleviated the volume expansion effect, shortened the diffusion distance of Li + , and accelerated Li + transport kinetics. Moreover, the large specific surface and mesoporous structure were beneficial to the diffusion of electrolyte as well as capacitive contribution.

“…To provide insight into lithium-storage property of this Fe 3 O 4 @NC material, we deeply investigated electrochemical reaction mechanism rooted in a CV method, which was performed by the above-mentioned cycled cell. In previous literature and our group's works, 10,25,40,41 we have found that there were two types of lithium-storage mechanisms, including conversion reaction and pseudo-capacitance behavior to contribute reversible capacity. Following a previously reported approach, we first obtained the voltammetric curves at different sweep rates (Figure 4a) and then determined the correlativity between the sweep rate and the current response, depending on eq 2: 42,43 = i av b (2) where i is the peak current, v is the sweep rate, and a and b are adjustable values.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 85%

“…Transition-metal oxides (TMOs), as a family of depending on conversion-type reaction mechanism, are very attractive materials, because of their high theoretical capacity (700–1000 mAh g –1 ) and reliable safety within a wide range of voltage. − Thus, this family, including magnetite (Fe 3 O 4 ), has shown extraordinary promise for electrochemical energy storage. Unfortunately, their potentials are usually limited, because of poor conductivity, hysteretic kineticsm and unstable structure, particularly volume expansion. − To address those formidable issues, a frequently used strategy is to design rational micro/nano architectures, such as nanosheet, nanorod, and hollow structure, etc., which have exhibited a distinct advantage on electrochemical performance, as compared with their bulk counterparts. ,,− For example, hierarchical hollow Fe 3 O 4 microspheres prepared by a controlled thermal decomposition route showed high specific capacity and enhanced cycle stability (750 mAh g –1 at 2.8 A g –1 , up to 50 cycles) . As is well-known, a hollow structure has sufficient interior space and, therefore, can accommodate the drastic volume expansion upon lithiation.…”

Section: Introductionmentioning

confidence: 99%

Self-Formed Channel Boosts Ultrafast Lithium Ion Storage in Fe₃O₄@Nitrogen-Doped Carbon Nanocapsule

Duan

ACS Appl. Mater. Interfaces

Chen

et al. 2019

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Investigations into conversion-type materials such as transition-metal oxides have dominated in energy-storage systems, especially for lithium ion batteries in recent years. A common understanding of taking account of high energy density and high power density allows us to design reasonable electrodes. In this study, the unique Fe3O4@nitrogen-doped carbon (denoted as Fe3O4@NC) nanocapsule with self-formed channels was synthesized based on a facile hydrothermal-coating-annealing route. With respect to the effect of this rational architecture on lithium-storage performance, excellent behavior (a high reversible capacity of 480 mAh g–1) could be maintained at 20 A g–1 during 1000 cycles, with an average Coulombic efficiency of 99.97%. It also means that such a Fe3O4@NC electrode can meet a fast-charge challenge (end-of-charge within ∼2 min). By a series of investigations, we certainly considered that uniform carbon coating improved electrical conductivity and acted as a buffer layer to accommodate volume variations of Fe3O4 nanoparticles during cycling. It is more interesting that self-formed channels can effectively shorten the ion diffusion path and provide a necessary space to buffer volume expansion as well. Benefiting from these synergetic advantages, this Fe3O4@NC nanocapsule also delivered outstanding electrochemical performances in full cells.