Surface Roughness: A Crucial Factor To Robust Electric Double Layer Capacitors

ACS Appl. Energy Mater.

et al. 2020

As a class of electrode materials for electric double-layer capacitors (EDLCs), carbon dots (CDs) are able to enlarge specific surface areas, fabricate hierarchical pores, and graft pseudocapacitive groups, leading to additional capacities and superior energy densities. In this work, the commercial polyacrylamide gel (PAMG) is used as a good host for CDs, which has continuously interconnected pores, a cross-linked network, and good swelling capacity so as to form continuous conductive carbon skeleton. After a one-step calcination–activation treatment, CDs are fused onto the final carbon architecture to form a series of porous carbon materials with specific functional groups. Different kinds of CDs, including the oxygen-doped, the nitrogen-doped, and the oxygen, nitrogen co-doped ones, are employed to prepare such carbon materials and tested, respectively. All of these materials have high specific surface areas, well-balanced pore size distributions, high conductivity, abundant superficial functional groups, and good wettability. When they are assembled as electrodes in EDLC, they exhibit remarkable performances, such as specific capacitance of 401–483 F g–1, rate stability over 75% (1–30 A g–1), energy density of 17–23 Wh kg–1, and cycling life of nearly 100%. These results prove that our method, calcination–activation on the CDs–porous (hydro)gel composites, is a universal route of preparing good carbon electrode materials for electrochemical energy storage.

Section: Resultsmentioning

confidence: 99%

Integrating Carbon Dots with Porous Hydrogels to Produce Full Carbon Electrodes for Electric Double-Layer Capacitors

Wei

Song

ACS Appl. Energy Mater.

et al. 2020

“…Smaller contact angles of below 11.9°o f these ICCM samples (Figure 3D−F) demonstrate the good wettability, which will play positive functions in reducing the interface resistance between electrode materials and electrolyte, thus improving the electrochemical performance of supercapacitors. 29 In contrast, a larger contact angle (16.4°, Figure S3, SI) of the Agglomerated-CDs sample illustrates that the aggregation effect will decrease the exposure of CDs to electrolyte and abate the positive interfacial interaction between the electrode and the electrolyte.…”

Section: Resultsmentioning

confidence: 97%

Integrated Carbon Dots-Matrix Structures: An Efficient Strategy for High-Performance Electric Double Layer Capacitors

Yang

ACS Appl. Energy Mater.

et al. 2020

Self Cite

As a type of nanomaterials that has received much attention, carbon dots (CDs) have played distinctive roles in various energy storage materials, benefiting from their advantages of controllable surface structures, good solubility, stable chemical properties, and low cost. However, noncontinuous structures of CDs will hinder their further application due to their unsatisfactory charge transfer performance. Here, we develop a series of carbon materials with CDs-carbon matrix structure based on mixed biogels and through a facile calcination−activation method. The potential applications of theses carbon materials have been demonstrated by electric double layer capacitors (EDLCs), where the optimal sample shows 500 F g −1 (1 A g −1 ) and the maximum rate of increment will be over 73% compared with that of an Agglomerated-CDs sample.

“…5.The variance analysis of MRR was shown in Table 7. (9,13), FL<F0.05 (5,8). Therefore, the regression model was significant and the lack of fit model was not significant.…”

Section: Fig 3 Proportion Of the Influence Of Parameters On Mrrmentioning

confidence: 88%

Material Removal Rate of Double-faced Mechanical Polishing of 4H-SiC Substrate

Yang

Qiu

2021

Preprint

Silicon carbide (SiC) has been a promising the-third-generation semiconductor power device material for high-power, high-temperature, substrate applications. It aims to improve the material removal rate (MRR), on the premise of ensuring the surface roughness requirements of the double-faced mechanical polishing of 6-inch SiC substrate. To obtain the relationship between any point on SiC substrate and polishing pads, the model about double-faced mechanical polishing has been built and the kinematics equations were created. Best optimized material removal rate parameters were obtained. MRR reached the maximum when speed rate of the outside ring gear to the inside sun gear m=-1, speed rate of lower plate to the inside sun gear n=5, SiC substrate distribution radius RB=75. The primary and secondary order of MRR (n>m>RB) was obtained. An accurate mathematical model of orthogonal rotary regression test of Tri-factor quadratic of MRR was established and the regression model was significant. Surface quality of SiC substrate was observed and characterized with SEM and AFM. It greatly provides a key guarantee for the next process of CMP, confirmed the importance of MRR to ultra-smooth polishing, and provides a guarantee for its application in semiconductor equipment and technology.