Model of micropore closure in hard carbon prepared from sucrose

Buiel, Edward; George, A.E.; Dahn, J. R.

doi:10.1016/s0008-6223(98)00335-2

Cited by 121 publications

(138 citation statements)

References 7 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…[ 37 ] Powder X-ray diffraction of all the samples showed refl ections around 2θ = 26 and 44 degrees, corresponding to the (002) and (100) planes of graphite ( Figure 4 a,b), respectively. Similar patterns have been observed by Buiel et al, [ 38 ] and the (002) peaks indicate the presence of several stacked graphene sheets within the CIO. We observed that smaller silica particles used in the synthesis of CIO resulted in larger interplanar distances.…”

Section: Resultssupporting

confidence: 87%

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Morelos-Gómez

Mani-González

Aliev

et al. 2014

Adv Funct Materials

View full text Add to dashboard Cite

Nitrogen-doped carbon inverse opal (CIO-N) is synthesized by a two-step process involving the infi ltration of carbon-nitrogen precursors within opals followed by the thermolysis and removal of the opal structure in hydrofl uoric acid (HF). Undoped samples exhibit a refl ection peak in the red region of the spectrum whereas N-doped samples display shifts to the blue region of the spectrum as the nitrogen content is increased. The degree of crystallinity of CIO-N strongly depends upon the nitrogen content and on the size of the precursor silica particles used to prepare the inverted opals. In addition, the introduction of nitrogen into the samples is able to increase the electrical conductivity by one order of magnitude from 2 to 30 S cm −1 (at room temperature). All samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis) spectroscopy, and electrical conductivity measurements. It is envisaged that CIO-N could have important applications in the fabrication of photonic crystals, photoconducting materials, molecular sensors, fi eld emission devices, capacitors, batteries, among many others.

show abstract

Section: Resultssupporting

confidence: 87%

Controlling the Optical, Electrical and Chemical Properties of Carbon Inverse Opal by Nitrogen Doping

Morelos-Gómez

Mani-González

Aliev

et al. 2014

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

“…32 Interestingly, the specific surface area can also be tuned by pre-treatments of the precursor 27,[33][34][35] or post pyrolysis treatment. 30 When the pyrolysis takes place under gas flow (typically Ar), the flow rate has also been found to have an effect in the specific surface area.…”

Section: Synthesis and Microstructurementioning

confidence: 99%

“…• C. 28,56 Since the pores are known to close at such temperatures 32 this indicates that closed pores are still accessible for Na + adsorption and that the average pore size is the main parameter controlling the capacity recorded for the low potential pseudo plateau.…”

Section: Electrochemical Performancementioning

confidence: 99%

Review—Hard Carbon Negative Electrode Materials for Sodium-Ion Batteries

Irisarri

Ponrouch

Palacin

2015

J. Electrochem. Soc.

558

436

View full text Add to dashboard Cite

A first review of hard carbon materials as negative electrodes for sodium ion batteries is presented, covering not only the electrochemical performance but also the synthetic methods and microstructures. The relation between the reversible and irreversible capacities achieved and microstructural features is described and illustrated with specific experiments while discussing also the effect of the electrolyte. A summary of the current knowledge is given while emphasizing the possibility of further performance improvements by thoroughly mastering structure-property relationships and also discussing the main current bottleneck to maximize energy density in real applications: the first cycle irreversible capacity. Finally, a short conclusion and perspectives session is provided highlighting necessary developments in the field to turn the present optimistic research prospects into tangible practical products. Intensive efforts aiming at the development of a sodium-ion battery (SIB) technology operating at room temperature and based on a concept analogy with the ubiquitous lithium-ion (LIB) have emerged in the last few years.1-6 Such technology would base on the use of organic solvent based electrolytes (commonly mixtures of alkylcarbonates with a dissolved sodium salt, typically NaPF 6 ) and two high and low potential operation electrodes which would exhibit reversible redox reactions involving sodium ions.In contrast to the large spectrum of suitable positive electrode materials identified, the choice is more restricted for the negative side, as is also the case for LIB. Indeed, sodium titanium oxides operating through intercalation reactions exhibit poor capacity retention 7,8 and alloy based electrodes 5 though promising at the laboratory scale, might suffer from practical bottlenecks derived from the large volumetric changes associated to their redox operation as is the case in LIB. 9,10 To date thus, only carbonaceous materials have practically proved viability.Most types of carbon react with lithium ions to a certain extent at low potential (∼0.1-1 V vs. Li + /Li) and are thus suitable for use as negative electrode materials. Hard carbons can deliver high capacity since the random alignment of small-dimensional graphene layers provides significant porosity able to accommodate lithium, 11 yet the rate capability (power performance) is usually limited and the irreversible capacity (mostly consumed in the formation of the Solid Electrolyte Interphase (SEI)) is higher than that of graphite. This fact coupled to its higher density which results in higher volumetric capacity has contributed to graphite being the most widely used commercial negative electrode material in LIB. Since graphite is not able to insert sodium ions 12,13 unless solvated to form ternary intercalation compounds, 14 non-graphitic carbons were already investigated a few years ago. 15,16These were found to exhibit first cycle reversible capacities in the range of 100-300 mAh/g with substantial fading upon cycling but still enabled the realization...

show abstract

“…We ascribe this to the common reorganizational dynamics at these temperatures that lead to closure of micropores. 55 The identification of the secondary templating phase is very difficult, because the underlying decomposition of MgCl 2 Á6H 2 O is a multistep process leading to a complex self-organization effect. We carried out PXRD measurements on unwashed samples (indicated by the suffix ''as-prepared'') prepared at temperatures down to 300 1C to relate salt phase transformation to the morphology generation (Fig.…”

Section: View Article Onlinementioning

confidence: 99%