Owing to their natural abundance, the low potential, and the low cost of potassium, potassium-ion batteries are regarded as one of the alternatives to lithium-ion batteries. In this work, we successfully fabricated a FeP/C composite, a novel electrode material for PIBs, through a simple and productive high-energy ball-milling method. The electrode delivers a reversible capacity of 288.9 mA•h•g −1 (2nd) at a discharge rate of 50 mA g −1 , which can meet the future energy storage requirements. Density functional theory calculations suggest a lower diffusion barrier energy of K + than Na + , which allows faster K + diffusion in FeP.

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The relation between viscosity and electrical conductivity of binary silicate melts is studied. The logarithm of viscosity varied linearly with the logarithm of conductivity. Furthermore, the lines are different for a MOSiO 2 system than for a M 2 O-SiO 2 system. Compared with the MO-SiO 2 system, the viscosity of the M 2 O-SiO 2 system decreases more with the increase in conductivity. Viscosity (g) is an important physicochemical property for high-temperature melts, which is closely related to metallurgical processes, such as extracting, refining, and continuous casting in steel making. Electrical conductivity (j) is another property that plays a prominent role in the modeling and operation of electric smelting furnaces. Both are sensitive to the structure change of silicate slag and exhibit an abrupt and complicated change with composition. So it is difficult to comprehend their composition dependence over wide composition ranges with only the available experimental data. Thus, pressing demands are being made for a model to estimate them over a broad composition range. Many models have been developed to predict viscosity [1][2][3][4][5][6][7][8] and electrical conductivity. [9,10] However, little research has been focused on the relationship between viscosity and electrical conductivity of silicate melts. Mills pointed out that both properties can be well correlated by the nonbridging oxygen per tetrahedrally coordinated cation (NBO/T) or revised optical basicity [11] ; therefore, some relation may exist between them. Walden's rule [12] is the first quantitative expression for viscosity and electrical conductivity, which shows that their product for an ionic liquid is constant related to the physical property of ion. However, Walden's rule is not strictly satisfied in the oxide melt because of the obvious differences between the activation energy of viscosity and the conductivity. [13] Later, Kato and Minowa [14] studied the relation in CaO-Al 2 O 3 -SiO 2 -based melts and gave the relationship in the product of gj n . Based on plenty of experimental viscosity data and the electrical conductivity model, [10] the present author gave a more accurate relation for CaO-Al 2 O 3 -SiO 2 and CaO-MgOAl 2 O 3 -SiO 2 aluminosilicate systems. [15] However, the previous studies only cover a narrow composition range in a few systems. Therefore, it is necessary to investigate whether this relations is suitable for other slag systems. Furthermore, the influence of different metal oxide on the relation between viscosity and conductivity is still unclear. In this study, MgO-SiO binary systems are studied.The viscosity and electrical conductivity of melts are structure dependent, and both change sharply as the melt structure changes. In general, the influence of different component on the melt structure is different. The acidic oxide SiO 2 can form the so-called siliconoxygen tetrahedron in which the Si cation is located at the center of the tetrahedron and oxygen anions are located at the corners. By sharing the oxygen ions, the...

Several models have been proposed to estimate the viscosity of molten slag using optical basicity. In this work, a new method for viscosity estimation of silicate slag using optical basicity has been proposed. The temperature dependence of viscosity was described by the general Arrhenius equation, and the contributions of bridging oxygen (O 0 ), non-bridging oxygen (O 2 ) and free oxygen (O 22 ) to viscous activation energy in this equation were taken into account. Compositions of three types of oxygen were calculated from optical basicity using the Toop-Samis model combined with the method proposed by Ottonello and Moretti. The present method has been applied to estimate the viscosity of silicate slag in CaO-FeO-MgO-MnO-SiO 2 system. The comparison between estimated and experimental values shows good agreements, with a mean deviation of ,20%.