The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking ad...The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking advantages of the synergistic effects of the activated Si nanoparticles and conductive flower-like MXene microspheres with ample ion-diffusion pathways. Consequently,the intrinsic MXene nanosheets with intelligently regulated interlayer spacing can accommodate the volume change induced strain during cycling, and the strong interaction between the Si and MXene matrix greatly contributes to the robust structural stability. As expected, the Si/MXene composite architecture exhibits boosted sodium storage performance, in terms of an inspiring reversible capacity of 751 mAh·g^(-1)at 0.1 A·g^(-1), remarkable long-term cycling stability of 376 mAh·g^(-1)at 0.1 A·g^(-1) over 500 cycles, and outstanding rate capability(after one consecutive current density changing from 0.1 to 2.0 A·g^(-1), a large capacity of 275 mAh·g^(-1) is regained after suddenly returning the initial current density back to 0.1 A·g^(-1) and in the subsequent 200 cycles this composite architecture anode still delivers a capacity of 332 mAh·g^(-1)). The kinetics analysis indicates superior pseudocapacitive property, high electronic conductivity, and favorable sodium-ion adsorption and diffusion capability,confirming fast sodium storage performance. Impressively, ex-situ X-ray diffraction and selected area electron diffraction characterizations corroborate the formation of NaSi;as the main sodiation products during the reversible evolutions of cycled proceeding with sodium-ion insertion. This work sheds light on the elaborate design of silicon-based nanostructured anodes towards advanced high-performance sodium-ion batteries.展开更多
In modern energy-saving replication storage systems, a primary group of disks is always powered up to serve incoming requests while other disks are often spun down to save energy during slack periods. However, since n...In modern energy-saving replication storage systems, a primary group of disks is always powered up to serve incoming requests while other disks are often spun down to save energy during slack periods. However, since new writes cannot be immediately synchronized into all disks, system reliability is degraded. In this paper, we develop a high-reliability and energy-efficient replication storage system, named RERAID, based on RAID10. RERAID employs part of the free space in the primary disk group and uses erasure coding to construct a code cache at the front end to absorb new writes. Since code cache supports failure recovery of two or more disks by using erasure coding, RERAID guarantees a reliability comparable with that of the RAID10 storage system. In addition, we develop an algorithm, called erasure coding write （ECW）, to buffer many small random writes into a few large writes, which are then written to the code cache in a parallel fashion sequentially to improve the write performance. Experimental results show that RERAID significantly improves write performance and saves more energy than existing solutions.展开更多
基金the National Natural Science Foundation of China(No.21703209)Shanxi Province Science Foundation(No.201901D211270)+1 种基金Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi,Key Research and Development(R&D)Projects of Shanxi Province(No.201803D121037)the Specialized Research Fund for Sanjin Scholars Program of Shanxi Province and the Graduate Student Education Innovation Projects of Shanxi Province。
文摘The fast and reversible sodiation/desodiation of anode materials remains an indelible yet fascinating target.Herein, a class of the densely packed Si/MXene composite microspheres is constructed and prepared, taking advantages of the synergistic effects of the activated Si nanoparticles and conductive flower-like MXene microspheres with ample ion-diffusion pathways. Consequently,the intrinsic MXene nanosheets with intelligently regulated interlayer spacing can accommodate the volume change induced strain during cycling, and the strong interaction between the Si and MXene matrix greatly contributes to the robust structural stability. As expected, the Si/MXene composite architecture exhibits boosted sodium storage performance, in terms of an inspiring reversible capacity of 751 mAh·g^(-1)at 0.1 A·g^(-1), remarkable long-term cycling stability of 376 mAh·g^(-1)at 0.1 A·g^(-1) over 500 cycles, and outstanding rate capability(after one consecutive current density changing from 0.1 to 2.0 A·g^(-1), a large capacity of 275 mAh·g^(-1) is regained after suddenly returning the initial current density back to 0.1 A·g^(-1) and in the subsequent 200 cycles this composite architecture anode still delivers a capacity of 332 mAh·g^(-1)). The kinetics analysis indicates superior pseudocapacitive property, high electronic conductivity, and favorable sodium-ion adsorption and diffusion capability,confirming fast sodium storage performance. Impressively, ex-situ X-ray diffraction and selected area electron diffraction characterizations corroborate the formation of NaSi;as the main sodiation products during the reversible evolutions of cycled proceeding with sodium-ion insertion. This work sheds light on the elaborate design of silicon-based nanostructured anodes towards advanced high-performance sodium-ion batteries.
基金Project supported by the National Natural Science Foundation of China （Nos. 61472152, 614320{37, 61572209, and 61300047）, the Fundamental Research Funds for the Central Universities, China （No. 2015QN069）, the Director Fund of Wuhan National Laboratory for Optoelectronics （WNLO）, and the MOE Key Laboratory of Data Storage System, China
文摘In modern energy-saving replication storage systems, a primary group of disks is always powered up to serve incoming requests while other disks are often spun down to save energy during slack periods. However, since new writes cannot be immediately synchronized into all disks, system reliability is degraded. In this paper, we develop a high-reliability and energy-efficient replication storage system, named RERAID, based on RAID10. RERAID employs part of the free space in the primary disk group and uses erasure coding to construct a code cache at the front end to absorb new writes. Since code cache supports failure recovery of two or more disks by using erasure coding, RERAID guarantees a reliability comparable with that of the RAID10 storage system. In addition, we develop an algorithm, called erasure coding write （ECW）, to buffer many small random writes into a few large writes, which are then written to the code cache in a parallel fashion sequentially to improve the write performance. Experimental results show that RERAID significantly improves write performance and saves more energy than existing solutions.
