Ao Han,Gang Wang,Wei Wang,Yu Zhao,Rujie He,Caiwang Tan
Negative coefficient of thermal expansion (Sr 0.2 Ba 0.8 )TiO 3 (SBT) nanoparticles are produced by ball milling and twice sintering process and coated with Cu foam (Cu f ) as an interlayer for brazing SiC and Nb. The influence of SBT content on the microstructural, shear strength, and fracture mechanism of SiC/Nb joints is investigated. In particular, SBT/Cu f foam is utilized to modify the coefficient of thermal expansion of the AgCuTi/SBT/Cu f /AgCuTi composite filler, resulting in a reduction of residual stresses in the joints. The residual stresses at the joints are calculated as well as analyzed the mechanism of residual stress relief by SBT. Following the introduction of the interlayer, the maximum shear strength of the joint is approximately 72 MPa, which is 164 % higher than the performance of the joint with uncoated SBT.
Liu Yang,Yang Jingdong,Wen Jiaxin,Ye Junliu,Liu Huan,Lu Liwei
Recently, rechargeable magnesium-ion batteries (MIBs) and rechargeable magnesium/lithium hybrid-ion batteries (MLHBs) have gained recognition as promising energy storage devices. However, the conventional CuS cathodes exhibit sluggish kinetics and poor cycle stability, thereby impeding the advancement and application of CuS. In this work, we have developed an economical and simple in-situ approach for synthesizing CuS@Cu foam (CSC) and evaluated its potential as a cathode material for both MIBs and MLHIBs. In both MIBs and MLHIBs, the CSC cathode demonstrates competitive performance. In MIBs, at a current density of 100 mA g −1 , the initial discharge specific capacity of the CSC is 150.94 mAh g −1 , which is higher than that of commercial CuS (3.99 mAh g −1 ). In MLHIBs, the CSC exhibits a discharge specific capacity of 502.95 mAh g −1 after 70 cycles at a current density of 100 mA g −1 , which significantly surpasses the discharge specific capacity of commercial CuS (229.52 mAh g −1 ). This performance improvement is attributed to the presence of Li + ions, which expedite the reaction kinetics, obviate the need for an activation process, and effectively facilitate the conversion reaction. In conclusion, by in-situ synthesis of CSC, the active material CuS firmly adheres to the Cu foam current collector. This approach is not only economical and simple but also significantly enhances the reactivity of the electrode material, thereby improving the electrochemical performance. This work provides valuable insights for the design, synthesis, and performance optimization of cathode materials of magnesium metal-based batteries.
Jianguo Duan,Xinshuai Yan,Kun Lei,Jianguo Cheng,Yaxiong Wang,Qingzong Su,Shimin Xu,Jianming Li,Qing Ma
The phase change materials (PCMs) are encapsulated into porous materials for collecting and storing heat energy has been widely used to overcome the intermittency of solar energy utilization. However, due to the inherent big pore structure and surface characteristics, metal porous materials are not ideal for PCM leakage-proof and slow photo-thermal response. To address these issues, A micro/nanostructured graphene-polyvinyl alcohol nanosheets/Cu(OH) 2 nanowire on a three-dimensional Cu foam (CF) to fill with PCM was designed and prepared. In the composite PCM, the polyvinyl alcohol/reduced graphene oxide (PRG) films coated on Cu(OH) 2 @Cu foam (CCF) provided a large number of active sites for the adsorption of modified paraffin wax (PWS). The prepared composite PCM has a stable structure and high thermal conductivity properties, meanwhile, the strong PRG films play a key role in enhancing leakage-proof and stability. The results show that the enthalpy value of PRG-CCF/PWS are 160.25 J·g −1 after 200 thermal cycles; which still maintains excellent cycle thermal reliability. In addition, under the simulated solar irradiation intensity is 120 mW·cm −2 , the heat storage rate and photo-thermal conversion efficiency of PRG-CCF/PWS are 1.37 J·s −1 and 90.25 %, respectively. It shows excellent photo-thermal response and uniform temperature distribution. This work provides an efficient, sustainable and affordable strategy for manufacturing high-performance composite PCM that can efficiently achieve solar energy utilization and energy management.
危险品化学品经营许可证（带存储）