Constructing mild expanded graphite microspheres by pressurized oxidation combined microwave treatment for enhanced lithium storage

Ma, Canliang; Hu, Zhenhui; Song, Ningjing; Zhao, Yun; Liu, Yanzhen; Wang, Huiqi

doi:10.1007/s12598-020-01625-9

Cited by 34 publications

(14 citation statements)

References 35 publications

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“…The amorphous nature of the hard carbon framework can be further proved by the Raman spectra (Figure h). The two broad peaks located at 1350 (D-band) and 1600 cm –1 (G-band) are characteristic of amorphous carbon. , On comparing the D- and G-band between d-MXene and (Si/d-MXene)@HC, the (Si/d-MXene)@HC displays a much higher intensity than d-MXene. The integrated area ratio of I D / I G for (Si/d-MXene)@HC is 1.33, slightly higher than that (1.25) of d-MXene, indicating that (Si/d-MXene)@HC has a higher disordering degree.…”

Section: Resultsmentioning

confidence: 99%

“…Sodium-ion batteries have recently attracted enormous attention as a promising candidate of lithium-ion batteries (LIBs) due to the abundant resource and low cost of sodium as well as the appropriate redox potential. − It is a great challenge, however, to find a suitable Na-storage anode material with high capacity and cycle stability because of the larger ionic radius of Na + (Na + : 1.02 Å vs Li + : 0.76 Å), − resulting in lower energy output and higher volume expansion during the Na + insertion/extraction. Among many attempted anode materials of SIBs, silicon (Si) has drawn special attention because of its sizeable theoretical capacity (954 mAh g –1 , NaSi), , economical efficiency, and nontoxicity.…”

Section: Introductionmentioning

confidence: 99%

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Lattice-Coupled Si/MXene Confined by Hard Carbon for Fast Sodium-Ion Conduction

Gou

Jing

Liu

et al. 2021

ACS Appl. Energy Mater.

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Silicon (Si) has been ascertained as one of the most desirable anode candidates for sodium-ion batteries (SIBs), ascribed to its sizeable theoretical capacity and abundant resource. However, the inherent electrochemical inertness of crystalline Si against sodium impedes its practical use. Herein, lattice-coupled Si nanoparticles are uniformly distributed onto delaminated MXene (d-MXene) and further tightly confined by hard carbon (HC), consequently forming a 3D cross-linked (Si/d-MXene)@HC architecture as an anode material for SIBs. Coupling a carboncoated Si anode with a conductive d-MXene matrix through the local lattice overlapping not only vastly enables the alloying reactivity of Si with Na, but also provides fast-transfer portholes for Na + and electrons because of the capacitive-like behavior of d-MXene, thus increasing the capacity and achieving fast ion conduction. The Si/d-MXene bonded with HC, constructing a robust architecture, can effectively stabilize the whole electrode structure and accommodate the volume expansion of Si upon cycling and increase capacitive-like contributions, resulting in an enhanced capacity and excellent cycle performance as anodes for SIBs. The developed electrode thus harvests favorable electrochemical performance compared to pure Si and d-MXene electrodes, such as high initial discharge capacity (370 mAh g −1 ), long cycling stability (a capacity retention above 80% after 500 cycles), and superior rate performance. The protocol to enable the sodium storage performance of Si/MXene anodes by adopting the capacitive-battery dual model would inspire rather far-ranging investigations on other advanced battery systems.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lattice-Coupled Si/MXene Confined by Hard Carbon for Fast Sodium-Ion Conduction

Gou

Jing

Liu

et al. 2021

ACS Appl. Energy Mater.

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“…Meanwhile, the low-frequency line represents the lithium diffusion process within the host of Si@void@C and Si@void@C-MEGMs. 23 The charge-transfer and electrochemical reaction resistances of MEGMs, 32 Si@void@C, and Si@void@C-MEGMs electrodes are 78, 112, and 90 Ω, respectively. It suggests that the impedance of Si@void@C-MEGMS is significantly reduced after being combined with MEGMs.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we have developed a gentle and facile method combining pressurized oxidation and microwave treatment to prepare mildly expanded graphite microspheres (MEGMs) with low expansion volume (less than 10 mL/g). 32 Herein, to develop the electrochemical advantages of Si@void@C nanospheres and solve the problems faced in practical applications, we strive to introduce MEGMs into the preparation of Si/C nanocomposite materials. It is found that the Si@void@C nanosphere evenly dispersed on the layers and pores of MEGMs, which is just like a grape that Si@ void@C nanospheres are the bunches of grapes and the layers of MEGMs are the grape leaves.…”

Section: Introductionmentioning

confidence: 99%

“…MEGMs were prepared by modified pressurized oxidation and a microwave treatment method, which have been covered in detail in our previous article. 32 Typically, SG-17 (1.0 g), KMnO 4 (0.2 g), and 5 mL concentrated H 2 SO 4 were added in sequence into a 25 mL PTFElined reactor at room temperature. After the reactor was sealed, it was put into an oven and heated to 75 °C for 30 min.…”

Section: Introductionmentioning

confidence: 99%

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Constructing a Grape-like Silicon/Mildly Expanded Graphite Microsphere Composite as a High-Performance Anode Material for Lithium-Ion Batteries

Song

et al. 2020

Energy Fuels

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This work reports that the use of a high-performance and low-cost micron carrier material with abundant load-bearing pores and stable conductive networks for silicon/carbon (Si/C) nanoparticles (NPs) could be an effective strategy to increase the practical use of Si/C anode materials for lithium-ion batteries (LIBs). It proposed for the first time mildly expanded graphite microspheres (MEGMs) as a micron carrier for yolk–shell structured Si/C (Si@void@C) nanospheres to construct a Si@void@C-MEGMs nano/microcomposite. Si@void@C nanospheres disperse on the nanosheets and pores of MEGMs, which is like bunches of grapes hanging between the branches and leaves of the grape. Accordingly, compared with Si@void@C nanospheres, this nano/microcomposite electrode exhibits a reversible specific capacity of 851.2 mAh/g after the rate test and the following 135 cycles at 100 mA/g. The microstructure and composition analysis indicates that the great electrochemical properties could be because the abundant pores and excellent conductivity of the MEGM carrier effectively improve the structure and cycling stability of Si@void@C nanospheres. This work has not only provided a high-performance Si@void@C-MEGMs nano/microcomposite but also verified that MEGMs are an effective and low-cost carrier for the Si@void@C NPs, which will benefit the commercial use of Si/C anode materials for LIBs.

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Sequential Effect of Dual‐Layered Hybrid Graphite Anodes on Electrode Utilization During Fast‐Charging Li‐Ion Batteries

Kang,

Lim,

Lee

et al. 2024

Advanced Science

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To recharge lithium‐ion batteries quickly and safely while avoiding capacity loss and safety risks, a novel electrode design that minimizes cell polarization at a higher current is highly desired. This work presents a dual‐layer electrode (DLE) technology via sequential coating of two different anode materials to minimize the overall electrode resistance upon fast charging. Electrochemical impedance spectroscopy and distribution of relaxation times analysis revealed the dynamic evolution of electrode impedances in synthetic graphite (SG) upon a change in the state of charge (SOC), whereas the natural graphite (NG) maintains its original impedance regardless of SOC variation. This disparity dictates the sequence of the NG and SG coating layers within the DLE, considering the temporal SOC gradient developed upon fast charging. Simulation and experimental results suggest that DLE positioning NG and SG on the top (second‐layer) and bottom (first‐layer), respectively, can effectively reduce the overall resistance at a 4 C‐rate (15‐min charging), demonstrating two times higher capacity retention (61.0%) over 200 cycles than its counterpart with reversal sequential coating, and is higher than single‐layer electrodes using NG or NG/SG binary mixtures. Hence, this study can guide the combinatorial sequence for multi‐layer coating of various active materials for a lower‐resistivity, thick‐electrode design.

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Constructing mild expanded graphite microspheres by pressurized oxidation combined microwave treatment for enhanced lithium storage

Cited by 34 publications

References 35 publications

Lattice-Coupled Si/MXene Confined by Hard Carbon for Fast Sodium-Ion Conduction

Lattice-Coupled Si/MXene Confined by Hard Carbon for Fast Sodium-Ion Conduction

Constructing a Grape-like Silicon/Mildly Expanded Graphite Microsphere Composite as a High-Performance Anode Material for Lithium-Ion Batteries

Sequential Effect of Dual‐Layered Hybrid Graphite Anodes on Electrode Utilization During Fast‐Charging Li‐Ion Batteries

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