scholarly journals Effect of Heat Treatment on the Microstructure and Performance of Cu Nanofoams Processed by Dealloying

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2691
Author(s):  
Jenő Gubicza ◽  
Péter Jenei ◽  
Gigap Han ◽  
Pham Tran Hung ◽  
Youngseok Song ◽  
...  

Cu nanofoams are promising materials for a variety of applications, including anodes in high-performance lithium-ion batteries. The high specific surface area of these materials supports a high capacity and porous structure that helps accommodate volume expansion which occurs as batteries are charged. One of the most efficient methods to produce Cu nanofoams is the dealloying of Cu alloy precursors. This process often yields nanofoams that have low strength, thus requiring additional heat treatment to improve the mechanical properties of Cu foams. This paper provides the effects of heat treatment on the microstructures, mechanical properties, and electrochemical performance of Cu nanofoams. Annealing was conducted under both inert and oxidizing atmospheres. These studies ultimately reveal the underlying mechanisms of ligament coarsening during heat treatment.

2020 ◽  
Vol 10 (23) ◽  
pp. 8428
Author(s):  
Arif Jumari ◽  
Cornelius Satria Yudha ◽  
Hendri Widiyandari ◽  
Annisa Puji Lestari ◽  
Rina Amelia Rosada ◽  
...  

Abundantly available SiO2 (silica) has great potential as an anode material for lithium-ion batteries because it is inexpensive and flexible. However, silicon oxide-based anode material preparation usually requires many complex steps. In this article, we report a facile method for preparing a SiO2/C composite derived from coal combustion fly ash as an anode material for Li-ion batteries. SiO2 was obtained by caustic extraction and HCl precipitation. Then, the SiO2/C composite was successfully obtained by mechanical milling followed by heat treatment. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Electrochemical properties were tested using an 18650 cylindrical cell utilizing LiNi0.8Co0.15Al0.05O2 (NCA) as the counter electrode. Based on the obtained results, the physiochemical characteristics and electrochemical performance, it was determined that SiO2/C composites were greatly affected by the temperature of heat treatment. The best result was obtained with the SiO2 content of 10% w/w, heating temperature of 500 °C, initial specific discharge capacity of 586 mAh g−1 at 0.1 C (1 C = 378 mAh g−1), and reversible capacity of 87% after 20 cycles. These results confirmed that the obtained materials had good initial discharge capacity, cyclability, high performance, and exhibited great potential as an anode material for LIBs.


2021 ◽  
Vol 9 ◽  
Author(s):  
Mingxuan Guo ◽  
Haibo Li

In this work, Mil-88B(Fe) is modified by a facile hydrolysis method for high-performance lithium ion battery (LIB). The hydrolyzed Mil-88B(Fe) [H-Mil-88B(Fe)] heritages the spindle-like shape of Mil-88B(Fe) and forms a porous structure, which possesses relatively high specific surface area (427.86 m2 g−1). It is 15 times higher than that of pristine Mil-88B(Fe). As anode for LIB, it reaches to high specific capacity of 600.1 mAh g−1 after 100 cycles at 100 mA g−1, while it is 312.5 mAh g−1 for pure Mil-88B(Fe). Furthermore, the kinetic analysis on i=avb reveals that the b value of H-Mil-88B(Fe) is 0.888, which suggests the mixed contribution from the diffusion and capacity reactions. Furthermore, the capacitance contribution fractions of H-Mil-88B(Fe) are 47.6%, 53.28%, 56.88%, 74.68%, and 69.14% at the sweep rate of 0.2, 0.4, 0.6, 0.8, 1.0 mV s−1, respectively, demonstrating a capacitance-dominated charge storage process at fast charging rates.


2013 ◽  
Vol 749 ◽  
pp. 1-6
Author(s):  
Ji Xing Lin ◽  
Jun Ping Zhang ◽  
Li Yuan Niu ◽  
Da Ren Sun ◽  
Zi Mu Shi ◽  
...  

In this study, Strontium (Sr) was added as modifier during the casting of Al-11.6Si-0.5Mg alloy, and the effect of T6 heat treatment on microstructure and performance of alloy was also investigated. The results showed that the 0.3% Al-8%Sr master alloy can refine effectively the α-Al dendrite and eutectic structure; the best economic process of T6 heat treatment is solution at 535°C for 6 hrs., and water cooling at 50~60°C,aging at 160°C for 6 hrs , then air cooling. After Sr modification and T6 heat treatment, the mechanical properties of alloy are improved remarkably, i.e., the tensile strength increased to 348MPa from 183MPa before modification and the elongation raises from 3.0% to 6.5%. So this alloy is applied to the strain clamp products in electric power fitting industry.


2019 ◽  
Vol 14 ◽  
pp. 155892501989525
Author(s):  
Yu Yang ◽  
Yanyan Jia

Ultrafine crystallization of industrial pure titanium allowed for higher tensile strength, corrosion resistance, and thermal stability and is therefore widely used in medical instrumentation, aerospace, and passenger vehicle manufacturing. However, the ultrafine crystallizing batch preparation of tubular industrial pure titanium is limited by the development of the spinning process and has remained at the theoretical research stage. In this article, the tubular TA2 industrial pure titanium was taken as the research object, and the ultrafine crystal forming process based on “5-pass strong spin-heat treatment-3 pass-spreading-heat treatment” was proposed. Based on the spinning process test, the ultimate thinning rate of the method is explored and the evolution of the surface microstructure was analyzed by metallographic microscope. The research suggests that the multi-pass, medium–small, and thinning amount of spinning causes the grain structure to be elongated in the axial and tangential directions, and then refined, and the axial fiber uniformity is improved. The research results have certain scientific significance for reducing the consumption of high-performance metals improving material utilization and performance, which also promote the development of ultrafine-grain metals’ preparation technology.


RSC Advances ◽  
2019 ◽  
Vol 9 (60) ◽  
pp. 35045-35049
Author(s):  
Xu Chen ◽  
Jian Zhou ◽  
Jiarui Li ◽  
Haiyan Luo ◽  
Lin Mei ◽  
...  

High-performance lithium ion batteries are ideal energy storage devices for both grid-scale and large-scale applications.


2016 ◽  
Vol 688 ◽  
pp. 44-49 ◽  
Author(s):  
Iveta Čabalová ◽  
František Kačík ◽  
Tereza Tribulová

Samples prepared from oak (Quercusrobur L.) wood were exposed to heat treatment at temperatures of 160, 180, 200 and 220 oC for 3, 6, 9 and 12 hours. In both untreated and thermally treated wood there were determined extractives and lignin by National Renewable Energy Laboratory (NREL) procedures, cellulose by Seifert's method, holocellulose according to Wise, hemicelluloses as difference between holocellulose and cellulose. Monosaccharides were determined by high performance liquid chromatography (NREL).The results show that hemicelluloses are less stable at thermal treatment than cellulose. The amounts of lignin and extractives rose by increasing both temperature and time of the treatment while the amounts of hemicelluloses decreased. Thermal treatment also resulted in significant decreases of the yields of non-glucosic saccharides. Degradation of carbohydrates can cause the deterioration of mechanical properties of wood.


2021 ◽  
Vol 22 (20) ◽  
pp. 11041
Author(s):  
Yajing Yan ◽  
Yanxu Chen ◽  
Yongyan Li ◽  
Xiaoyu Wu ◽  
Chao Jin ◽  
...  

By virtue of the high theoretical capacity of Si, Si-related materials have been developed as promising anode candidates for high-energy-density batteries. During repeated charge/discharge cycling, however, severe volumetric variation induces the pulverization and peeling of active components, causing rapid capacity decay and even development stagnation in high-capacity batteries. In this study, the Si/Fe2O3-anchored rGO framework was prepared by introducing ball milling into a melt spinning and dealloying process. As the Li-ion battery (LIB) anode, it presents a high reversible capacity of 1744.5 mAh g−1 at 200 mA g−1 after 200 cycles and 889.4 mAh g−1 at 5 A g−1 after 500 cycles. The outstanding electrochemical performance is due to the three-dimensional cross-linked porous framework with a high specific surface area, which is helpful to the transmission of ions and electrons. Moreover, with the cooperation of rGO, the volume expansion of Si is effectively alleviated, thus improving cycling stability. The work provides insights for the design and preparation of Si-based materials for high-performance LIB applications.


2013 ◽  
Vol 690-693 ◽  
pp. 58-61
Author(s):  
Gui Rong Yang ◽  
Wen Ming Song ◽  
Ying Ma ◽  
Yuan Hao

The copper specimen was fabricated through liquid die forging under optimum technical parameter, and the die forging copper was annealed under different conditions. The effect of annealing treatment on the microstructure, strength, hardness and electric conductivity of die forging copper was investigated. The results show that the microstructure of die forging copper was changed into equiaxed grain when the treating temperature was less than 250 °C and treating time was less than 2.0 h. The restoration and recrystallization happened during treatment and the obtained crystal grain size became smaller. The strength of die forging copper decreased after annealing treatment owing to the decreasing of dislocation density and concentration of supersaturated vacancy. The hardness of die forging copper also dropped to some extent. The electric conductivity of die forging copper was increased by 5.2% after annealing treatment because the concentration of supersaturated vacancy and dislocation density was decreased obviously.


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