Introduction to achievements
It is an urgent need to introduce inherent defects into porous carbon skeleton reasonably to expand the utilization range of carbon materials, but it is still a challenge. In this article, Professor Li Yongfeng of Youshi University in China published an article entitled "Advanced Supercapacitor A with Porous Carbon Nanoplates with Intrinsic Defects Synthesized by Potassium Citrate Tower" in Carbon Magazine. Nd microwave absorption ",a simple and effective strategy is proposed. Porous carbon nanosheets rich in internal defects were prepared in sealed tubes (S-PCN) with potassium citrate as the sole raw material.
The internal pressure in the sealed tube will lead to the formation of internal defects, and the density of defects can be adjusted by the volume of the sealed tube. The obtained S-PCN has reasonable pore structure and uniformly distributed inherent defects. Due to the redistributed surface charge, enhanced wettability and electrochemical surface area,-1 is at an ultra-high power density of 50 kW kg-1. In addition, high-density inherent defects will also bring strong polarization loss and balanced impedance matching. Therefore, the best S-PCN as an electromagnetic wave absorber shows the maximum reflection loss as high as -58.2 dB, which means that almost all the incident microwaves can be effectively consumed.
Graphic reading guide
Figure 1. (a) Schematic diagram of S-PCN synthesis and its dual application.
Figure 2. (a) scanning electron microscope images of K2CO3 @ o-HCC, (b, c) O-HCC, (d) K 2 CO 3 @S-PCN-3 and (e, f) S-PCN-3; (g) TEM images, (h) HRTEM images, and (i) SAED patterns of I)HCC; (j) TEM image of S-PCN-3, (k) HRTEM image and (l) SAED pattern.
Figure 3. (a) Raman spectrum, (b) C 1s spectrum, (c) EPR spectrum, (d) dynamic water contact angle measurement, (e) nitrogen adsorption-desorption isotherm, and (f) O-HCC and S-PCNs. Illustration (f) Enlargement of the middle hole partition.
Figure 4. Electrochemical properties of samples in three-electrode system.
Figure 5. Electrochemical properties of SC.
Figure 6. (a) reflection loss curve of O-HCC, (b) S-PCN- 1, (c) S-PCN-2 and (d) S-PCN-3. (e) the dielectric loss tangent of O-HCC and S-PCN and (f) the modulus of Zi in-1 (g) The performance comparison of S-PCN-3MA and the absorbent reported recently.
summary
In a word, porous carbon nanosheets rich in intrinsic defects were successfully prepared by direct pyrolysis of potassium citrate in a sealed tube. This work provides a new idea for preparing porous carbon materials rich in inherent defects.
Literature: https://doi.org/10.1016/j.carbon.2021.06.072.