4-丙基硫酸乙烯酯(PDTD)作为电解液添加剂被用于提升高压4.5 V LiNi_(0.85)Co_(0.1)Al_(0.05)O_(2)(NCA)的电极/电解液界面稳定性。当添加0.5 wt.%PDTD到基准电解液,即1.0 M LiPF_(6)溶解在碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)(1/2,w/w),Li/...4-丙基硫酸乙烯酯(PDTD)作为电解液添加剂被用于提升高压4.5 V LiNi_(0.85)Co_(0.1)Al_(0.05)O_(2)(NCA)的电极/电解液界面稳定性。当添加0.5 wt.%PDTD到基准电解液,即1.0 M LiPF_(6)溶解在碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)(1/2,w/w),Li/NCA电池循环300次后容量保持率由21.6%提升至62.6%。同时,PDTD能有效抑制Li/NCA电池的电压降,在基准电解液中,满电电池电压在400 h后急剧下降到2.0 V以下,而含添加剂电池电压则能保持极高的稳定性。电池循环后的电化学表征和电极物理表征证明了该添加剂有效提升了NCA正极/电解液界面稳定性,保护了电极材料。展开更多
Concave surfaces focus sound while convex surfaces disperse sound. It is therefore interesting to know if it is possible to make use of these two opposite characteristics to enhance the band gap performance of periodi...Concave surfaces focus sound while convex surfaces disperse sound. It is therefore interesting to know if it is possible to make use of these two opposite characteristics to enhance the band gap performance of periodic arrays of solid cylinders in air. In this paper, the band gap characteristics of a 2-D square array of semi-hollow circular cylinders embedded in air are investigated, both experimentally and theoretically. In comparison with the types of inclusion studied by previous researchers, a semi-hollow circular cylinder is unique in the sense that it has concave inner surfaces and convex outer surfaces. The finite difference time domain (FDTD) method is employed to study the propagation behavior of sound across the new phononic crystal of finite extent, and the influences of sample size and inclusion orientation on band gap characteristics are quantified in order to obtain the maximum band gap. For reference, the band gap behaviors of solid circular cylinder/air and hollow circular cylinder/air systems are considered and compared with those of semi-hollow circular cylinder/air systems. In addition to semi-hollow circular cylinders, other inclusion topologies such as semi-hollow triangular and square cylinders are also investigated. To validate the theoretical predictions, experimental measurements on square arrays of hollow Al cylinders in air and semi-hollow Al cylinders in air are carried out. The results demonstrate that the semi-hollow circular cylinder/air system has the best overall band gap performance.展开更多
文摘4-丙基硫酸乙烯酯(PDTD)作为电解液添加剂被用于提升高压4.5 V LiNi_(0.85)Co_(0.1)Al_(0.05)O_(2)(NCA)的电极/电解液界面稳定性。当添加0.5 wt.%PDTD到基准电解液,即1.0 M LiPF_(6)溶解在碳酸乙烯酯(EC)/碳酸甲乙酯(EMC)(1/2,w/w),Li/NCA电池循环300次后容量保持率由21.6%提升至62.6%。同时,PDTD能有效抑制Li/NCA电池的电压降,在基准电解液中,满电电池电压在400 h后急剧下降到2.0 V以下,而含添加剂电池电压则能保持极高的稳定性。电池循环后的电化学表征和电极物理表征证明了该添加剂有效提升了NCA正极/电解液界面稳定性,保护了电极材料。
基金Supported by the National Basic Research Program of China ("973" Project) (Grant Nos.2006CB601202,2006CB601204)the National Natural Science Foundation of China (Grant Nos.50676075,10572111,10632060)+1 种基金the National 111 Project of China (Grant No.B06024)the National High Technology Research and Development Program of China ("863" Project) (Grant No.2006AA03Z519)
文摘Concave surfaces focus sound while convex surfaces disperse sound. It is therefore interesting to know if it is possible to make use of these two opposite characteristics to enhance the band gap performance of periodic arrays of solid cylinders in air. In this paper, the band gap characteristics of a 2-D square array of semi-hollow circular cylinders embedded in air are investigated, both experimentally and theoretically. In comparison with the types of inclusion studied by previous researchers, a semi-hollow circular cylinder is unique in the sense that it has concave inner surfaces and convex outer surfaces. The finite difference time domain (FDTD) method is employed to study the propagation behavior of sound across the new phononic crystal of finite extent, and the influences of sample size and inclusion orientation on band gap characteristics are quantified in order to obtain the maximum band gap. For reference, the band gap behaviors of solid circular cylinder/air and hollow circular cylinder/air systems are considered and compared with those of semi-hollow circular cylinder/air systems. In addition to semi-hollow circular cylinders, other inclusion topologies such as semi-hollow triangular and square cylinders are also investigated. To validate the theoretical predictions, experimental measurements on square arrays of hollow Al cylinders in air and semi-hollow Al cylinders in air are carried out. The results demonstrate that the semi-hollow circular cylinder/air system has the best overall band gap performance.
