JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Xudong Liu,Yong Liu,Shangli Dong,Xuefeng Zhang,Lu Lv,Sirui He
Constructing 3D porous MXene from 2D nanosheets is the most efficient method to avoid restacking of nanosheets and enhance the application of nanomaterials at macroscale. Direct foaming from solids is an ideal means to obtain 3D porous structure. However, MXene is difficult to be physically foamed because its plasticity is not enough. Herein, we invent a chemical foaming method to convert MXene films into foams with good porosity. The wet film of Ti 3 C 2 T x precursor with interlayer water has super high plasticity, which is more conducive to the introduction of foaming agent and the foaming process. The obtained Ti 3 C 2 T x foams exhibits good porosity and higher specific surface area than Ti 3 C 2 T x films, resulting in outstanding capacitive performance (426 F g −1 at 1 A g −1 ) with good rate performance (190 F g −1 at 10 A g −1 ) and excellent cycle stability (92% retention after 10,000 cycles). The supercapacitor fabricated with Ti 3 C 2 T x foams display an outstanding energy density of 14.1 Wh kg −1 at a power density of 250 W kg −1 . Moreover, the foaming method creates a up-bottom construction patterns, which is simple, low cost and easy for scalable fabricating porous MXene.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Kexuan Hu,Hehe Wang,Xiang Zhang,Hui Huang,Tai Qiu,Yang Wang,Chuanfang (John) Zhang,Limei Pan,Jian Yang
Light weight is one significant pursuit for microwave absorption (MA) materials. Generally, constructing foams with porous structure and low density as the absorber is one efficient way to reduce the absorber content and the quality of MA materials since the porous structure can effectively cause multiple reflections of electromagnetic waves and enhance the MA performance. Herein, we report a new and simple method for fabricating ultralight Ti 3 C 2 T x foams by hydrochloric acid induced self-assembly and freeze-drying, for which the pore structure and MA performance can be effectively regulated by pre-freezing temperature. The decrease of pre-freezing temperature from −20 °C to −196 °C results in a reduced pore size, more homogenous pore structure, a decreased electrical conductivity, a decreased dielectric constant and a significantly enhanced MA performance. 3.3 wt% Ti 3 C 2 T x foams was immersed into molten paraffin to prepare composites for the MA performance tests. Due to the synergy of multiple reflection, conductive loss and polarization relaxation, the Ti 3 C 2 T x foams pre-frozen at −196 °C shows the most superb and impressive MA performance, a minimum reflection loss (RL) of −50.6 dB at the thickness of 1.8 mm and an effective absorption bandwidth (EAB) of 4.2 GHz (13.8–17.6 GHz) at the thickness of 1.4 mm, and the EAB could be adjusted in a range of 11.9 GHz (6.1–18 GHz) by increasing the thickness from 1 mm to 3 mm. This is one of the most lightweight materials with excellent MA performance to our knowledge, which perfectly meet the combined pursuit of light weight, thin thickness, broad bandwidth and strong absorption. This work offers a simple strategy for constructing 3D porous Ti 3 C 2 T x -based foams facing the application such as MA, electromagnetic shielding, environmental governance, energy storage and sensors.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2021
·
IF 7.664
Tianpei Sun,Zhiwei Liu,Shuang Li,Hansong Liu,Fan Chen,Kai Wang,Yan Zhao
A MX/CF/Epoxy composite with a 3D network structure was prepared through a one-step impregnation method. Compared with the simple doping of MXene into the polymer matrix , the 3D structure greatly reduces the amount of absorbing filler while improving the microwave absorbing performance of epoxy resin, which realizes the economical and efficient use of absorbing agents. The MX/CF/Epoxy composite has a RL min of −41.46 dB when the content of MXene is only 0.337 wt% and CF is 1.183 wt% with a thickness of 1.83 mm. At the same time, the EVB of the composite can reach 4.67 GHz (10.58–15.25 GHz). The effective improvement on microwave absorbing performance of MX/CF/Epoxy composites is mainly due to the unique 3D foam structure, the interface polarization and dipole relaxation caused by surface functional groups and defects of MX/CF. This work provides new ideas for improving the application potential of epoxy resin-based composites in the field of microwave absorption.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Small
·
2022
·Vol. 18
·期 27
·2202203
·
IF 15.153
Ke Lv,Jizhen Zhang,Xu Zhao,Na Kong,Jinlong Tao,Ji Zhou
Wearable electronics demand energy storage devices with high energy density and fast charging-discharging rates. Although various porous electrodes have been constructed, the effect of pore size on the capacitive performance of 2D nanomaterials has been rarely studied. Herein, flexible MXene foams with significantly different pore structures are fabricated using varying diameter polystyrene (PS) spheres (80, 310, and 570 nm), which shows uniform pores and interconnected pores providing enough active sites and a good electrical connection for electron transfer. Noteworthy, when MXene flakes and templates (310 nm) have a similar size, the foam delivers the highest gravimetric capacitance of 474 ± 12 F g −1 at 2 mV s −1 than others. Additionally, the mass ratio between MXene and PS controls the packing density of foams influencing the inner resistance of foam electrodes. A carbon nanotube is introduced to further improve the electrical conductivity of foams to achieve a capacitance of 462 ± 8 F g −1 at 2 mV s −1 and retains 205 ± 10 F g −1 at 1000 mV s −1 , demonstrating promises in energy storage applications and providing an insightful guidance for designing 2D nanomaterials-based porous electrodes for supercapacitors.
研究领域:
材料科学
·
电化学
·
纳米技术
·
能量存储
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）