Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the el...Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the electrochemical hydrogen storage properties of the alloys before and after heat treatment. The results show that the maximum discharge capacity of heat-treated Ti2?xMgxNi alloy can reach 275.3 mA·h/g, which is 100 mA·h/g higher than that of the amorphous Ti2?xMgxNi alloy. The heat-treated Ti1.9Mg0.1Ni alloy presents the best cycling stability with a high discharge capacity of 210 mA·h/g after 30 cycles. The results of LP and potential-step measurement of the Ti1.9Mg0.1Ni alloy show that the exchange current density increases from 101.1 to 203.3 mA/g and the hydrogen diffusion coefficient increases from 3.20×10?11 to 2.70×10?10 cm2/s after the heat treatment, indicating that the heat treatment facilitates both the charge-transfer and hydrogen diffusion processes, resulting in an improvement in electrochemical hydrogen storage properties of Ti2?xMgxNi (x=0?0.3) alloys.展开更多
Heat and energy are conceptually different, but often are assumed to be the same without justification. An effective method for investigating diffusion properties in equilibrium systems is discussed. With this method,...Heat and energy are conceptually different, but often are assumed to be the same without justification. An effective method for investigating diffusion properties in equilibrium systems is discussed. With this method, we demonstrate that for one-dimensional systems, using the indices of particles as the space variable, which has been accepted as a convention, may lead to misleading conclusions. We then show that though in one-dimensional systems there is no general connection between energy diffusion and heat conduction, however, a general connection between heat diffusion and heat conduction may exist. Relaxation behavior of local energy current fluctuations and that of local heat current fluctuations are also studied. We find that they are significantly different,though the global energy current equals the globe heat current.展开更多
基金Project(51201089)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions of China
文摘Amorphous Ti2?xMgxNi (x=0?0.3) alloys were prepared by mechanical milling of elemental powders. Charge and discharge test, linear polarization (LP) and potential-step measurement were carried out to investigate the electrochemical hydrogen storage properties of the alloys before and after heat treatment. The results show that the maximum discharge capacity of heat-treated Ti2?xMgxNi alloy can reach 275.3 mA·h/g, which is 100 mA·h/g higher than that of the amorphous Ti2?xMgxNi alloy. The heat-treated Ti1.9Mg0.1Ni alloy presents the best cycling stability with a high discharge capacity of 210 mA·h/g after 30 cycles. The results of LP and potential-step measurement of the Ti1.9Mg0.1Ni alloy show that the exchange current density increases from 101.1 to 203.3 mA/g and the hydrogen diffusion coefficient increases from 3.20×10?11 to 2.70×10?10 cm2/s after the heat treatment, indicating that the heat treatment facilitates both the charge-transfer and hydrogen diffusion processes, resulting in an improvement in electrochemical hydrogen storage properties of Ti2?xMgxNi (x=0?0.3) alloys.
基金the National Natural Science Foundation of China (Grant Nos. 10925525, 11275159 and 10805036)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20100121110021)
文摘Heat and energy are conceptually different, but often are assumed to be the same without justification. An effective method for investigating diffusion properties in equilibrium systems is discussed. With this method, we demonstrate that for one-dimensional systems, using the indices of particles as the space variable, which has been accepted as a convention, may lead to misleading conclusions. We then show that though in one-dimensional systems there is no general connection between energy diffusion and heat conduction, however, a general connection between heat diffusion and heat conduction may exist. Relaxation behavior of local energy current fluctuations and that of local heat current fluctuations are also studied. We find that they are significantly different,though the global energy current equals the globe heat current.
