Tailoring stress in pyrolytic carbon for fabrication of nanomechanical string resonators

Quang, Long Nguyen; Larsen, Peter E.; Boisen, Anja; Keller, Stephan Sylvest

doi:10.1016/j.carbon.2018.03.005

Cited by 14 publications

(11 citation statements)

References 24 publications

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“…The structural change can be a part of relaxation of residual stress that develops within pyrolytic carbon derived from photoresist resins. [ 64 ] When sodium ions are inserted and consequently extracted, the microstructure of hard carbon could rearrange to relieve the residual stress, compacting the interlayer distance. There was another peak that appeared at 28° which continued growing until the discharging ended at 0.001 V. The intensity of this peak was lowered along with charging, yet did not completely fade at 2.0 V. A past publication reported a similar finding and attributed it to formation of an intercalation compound (NaCx).…”

Section: Resultsmentioning

confidence: 99%

A 3D‐Printed, Freestanding Carbon Lattice for Sodium Ion Batteries

Katsuyama

Kudo

Kobayashi

et al. 2022

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ephemeral forms of energy. In order to use the stored energy when needed and as fast as desired, batteries must exhibit high capacity and high power at an affordable cost. Researchers have made tremendous efforts to develop such technologies including silicon anodes for lithium-ion batteries (LIBs) with a gravimetric capacity an order of magnitude higher than graphite, [1][2][3] solid state electrolytes to improve the safety of batteries, [4] replacement of inorganic compounds by organic materials which requires less energy for mass production, [5][6][7][8][9] and substitution of lithium by other more abundant metals such as sodium, [10][11][12][13][14] potassium, [11] calcium, [15] magnesium, [16] aluminum, [17] and zinc. [17] Nevertheless, it still remains a challenging goal to simultaneously achieve high performance and low cost as they generally conflict with each other.One possible way to achieve this goal is to increase the mass loading of active materials in a single cell (Figure 1). [18][19][20][21][22][23][24][25] A single cell with 5 times thicker electrodes, instead of a stack of 5 cells, can reduce the amount of inactive components (separator, current collector, tabs, etc.) to one fifth, downsizing the overall cell size while saving as much as 26.1% of the cost per battery as shown in Table 1. [18] Based on the conventional film electrode fabrication process that uses a slurry containing the active materials as powders, increasing the amount of slurry per electrode is a simple concept. However, two problems arise: First, the kinetics of ion diffusion limits the maximum Increasing mass loadings of battery electrodes critically enhances the energy density of an overall battery by eliminating much of the inactive components, while compacting the battery size and lowering the costs of the ingredients. A hard carbon microlattice, digitally designed and fabricated by stereolithography 3D-printing and pyrolysis, offers enormous potential for high-mass-loading electrodes. In this work, sodium-ion batteries using hard carbon microlattices produced by an inexpensive 3D printer are demonstrated. Controlled periodic carbon microlattices are created with enhanced ion transport through microchannels. Carbon microlattices with a beam width of 32.8 µm reach a record-high areal capacity of 21.3 mAh cm −2 at a loading of 98 mg cm −2 without degrading performance, which is much higher than the conventional monolithic electrodes (≈5.2 mAh cm −2 at 92 mg cm −2 ). Furthermore, binder-free, pure-carbon elements of microlattices enable the tracking of structural changes in hard carbon that support the hypothesized intercalation of ions at plateau regions by temporal ex situ X-ray diffraction measurements. These results will advance the development of high-performance and low-cost anodes for sodium-ion batteries as well as help with understanding the mechanisms of ion intercalations in hard carbon, expanding the utilities of 3D-printed carbon architectures in both applications and fundamental studies.

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Section: Resultsmentioning

confidence: 99%

A 3D‐Printed, Freestanding Carbon Lattice for Sodium Ion Batteries

Katsuyama

Kudo

Kobayashi

et al. 2022

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“…For resonators pyrolysed at 1100 °C, the resistances were lower [Supporting Information S1]. However, for these structures, buckling due to compressive stress was observed 32 . In conclusion, the resonators fabricated at 900 °C had resistances in the kΩ range and were deemed suitable for resistive heating.…”

Section: Resultsmentioning

confidence: 99%

“…The thermal analysis of the polymers was based on resonance frequency measurements of the pyrolytic carbon resonators. The resonance frequency was tracked using a commercial MSA-500 laser Doppler vibrometer from Polytec and an HF2LI lock-in amplifier from Zurich Instruments as previously described 32 . For temperature calibration, external heating was used, and the chip with the pyrolytic carbon resonators was placed on top of a Peltier element.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, 3D pyrolytic carbon structures have been used for improving the sensor performance 27,28 or developing microbatteries 29,30 . Recently, pyrolytic carbon string resonators have been successfully fabricated with a simple and fast process 31,32 . The optimized micromechanical string resonators display excellent resonant behavior, which has been suitable for applications such as mass sensing and nanomechanical infrared (NAM-IR) spectroscopy 33 .…”

Section: Introductionmentioning

confidence: 99%

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Pyrolytic carbon resonators for micromechanical thermal analysis

Nguyen

Larsen

et al. 2019

Microsyst Nanoeng

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Thermal analysis is essential for the characterization of polymers and drugs. However, the currently established methods require a large amount of sample. Here, we present pyrolytic carbon resonators as promising tools for micromechanical thermal analysis (MTA) of nanograms of polymers. Doubly clamped pre-stressed beams with a resonance frequency of 233 ± 4 kHz and a quality factor (Q factor) of 800 ± 200 were fabricated. Optimization of the electrical conductivity of the pyrolytic carbon allowed us to explore resistive heating for integrated temperature control. MTA was achieved by monitoring the resonance frequency and quality factor of the carbon resonators with and without a deposited sample as a function of temperature. To prove the potential of pyrolytic carbon resonators as thermal analysis tools, the glass transition temperature (Tg) of semicrystalline poly(L-lactic acid) (PLLA) and the melting temperature (Tm) of poly(caprolactone) (PCL) were determined. The results show that the Tg of PLLA and Tm of PCL are 61.0 ± 0.8 °C and 60.0 ± 1.0 °C, respectively, which are in excellent agreement with the values measured by differential scanning calorimetry (DSC).

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“…On the one hand, the Joule heating process annealed the pre-existing critical flaws, preventing failure significantly below the average strength. On the other hand, it relieved the compressive residual stresses caused by the pyrolysis of the photoresists 68 , which can prevent crack propagation, and introduced surface defects, thus reducing the highest strengths recorded for as-pyrolyzed lattices. Therefore, the porous sheath is believed to contribute to the narrow deviation of compressive strength, suggesting surface nanoporosity as the preferred location where brittle failure is triggered.…”

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confidence: 99%

Nanographitic coating enables hydrophobicity in lightweight and strong microarchitected carbon

Kudo

Bosi

2020

Commun Mater

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Metamaterials that are lightweight, stiff, strong, scalable and hydrophobic have been achieved separately through different materials and approaches, but achieving them in one material is an outstanding challenge. Here, stereolithography and pyrolysis are employed to create carbon microlattices with cubic topology and a strut width of 60–70 µm, with specific strength and stiffness of up to 468.62 MPa cm3 g−1 and 14.39 GPa cm3 g−1 at a density of 0.55 g cm−3, higher than existing microarchitected materials and approaching those of the strongest truss nanolattices. Subsequent fast Joule-heating then introduces a hierarchical nanographitic skin that enables hydrophobicity, with a water contact angle of 135 ± 2°, improving the hydrophilic response of pyrolytic carbon. As the Joule heating induced sp2-hybridization and nano-texturing predominantly affect the strut sheath, the effect on mechanical response is limited to a reduction in the distribution of compressive strength of as-pyrolyzed architectures by ~80% and the increase of the mean effective stiffness by ~15%. These findings demonstrate a technique to fabricate high strength, low density, and hydrophobic nanographite-coated carbon microlattices.

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Tailoring stress in pyrolytic carbon for fabrication of nanomechanical string resonators

Cited by 14 publications

References 24 publications

A 3D‐Printed, Freestanding Carbon Lattice for Sodium Ion Batteries

A 3D‐Printed, Freestanding Carbon Lattice for Sodium Ion Batteries

Pyrolytic carbon resonators for micromechanical thermal analysis

Nanographitic coating enables hydrophobicity in lightweight and strong microarchitected carbon

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