Q.R. Yao

A high rate capability and long lifespan symmetric sodium-ion battery system based on a bipolar material Na2LiV2(PO4)3/C

Sodium ion batteries have been considered as one of the promising candidates for large-scale energy storage systems. From the application perspective of an integrated sodium ion full-cell system, it is important to develop a practical sodium-ion full-cell system with excellent cycling life, superior safety, and good rate capability to tolerate the frequent current impulses during the grid peak period. Therefore, exploring appropriate electrode materials with excellent electrochemical properties is the key issue. A rhombohedral structured two-phase Na2LiV2(PO4)3/C nanocomposite has been successfully synthesized and employed as both cathode and anode material. It exhibits excellent electrochemical performance, including high capacity, superior rate capability, and remarkable cycling performance. In particular, it shows excellent long-term cycling stability with a capacity retention of about 83% and 100% after 3000 cycles at 10C, for the cathode and anode, respectively. Moreover, the symmetric sodium-ion full cells made of the Na2LiV2(PO4)3/C nanocomposite have good rate capability and cycling stability, which verifies the feasibility of practical applications of the Na2LiV2(PO4)3/C nanocomposite in sodium-ion batteries.

Effect of Ce content on structure and electrochemical properties of La0.8–xCexPr0.1Nd0.1B5 (B = Ni, Co, Mn; 0 ⩽ x ⩽ 0.3) hydrogen storage alloys

The structure and electrochemical properties of La0.8–xCexPr0.1Nd0.1B5 (B5 ≡ Ni3.8Co1.1Mn0.1; x = 0, 0.1, 0.2, 0.3) hydrogen storage alloys have been investigated. The results show that all alloys consist of CaCu5-type single phase. The maximum discharge capacity of the alloy electrodes decreases from 368.7 mA h g–1 (x = 0) to 294.9 mA h g–1 (x = 0.30), the cyclic stability (S100) increases from 37.6% (x = 0) to 69.8% (x = 0.20) after 100 charge/discharge cycles, and the HRD1200 first increases from 69.5% (x = 0) to 85.2% (x = 0.20), then decreases to 80.8% (x = 0.30). Meanwhile, the electrochemical kinetic characteristics of the La0.8‒xCexPr0.1Nd0.1B5 alloy electrodes are also improved by increasing Ce content.

The isothermal section of the Tb–Co–Cr ternary system at 873 K

The isothermal section of the phase diagram of the Tb–Co–Cr ternary system at 873 K was investigated by means of X-ray diffraction, metallography, and scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. Ternary phases and their lattice parameters as a function of composition of solid solution were systematically studied. The existence of one ternary phase reported previously was confirmed. The ternary compound Tb(Co, Cr)12 crystallizes with ThMn12-type structure, space group I4/mmm. The linear homogeneity range along the line of 7.69 at.% Tb in TbCo12− x Cr x was found to be about x = 3.6–5.7, i.e., 27.7–43.8 at.% Cr. The lattice parameters are a = 0.8326–0.8352 nm and c = 0.4709–0.4740 nm. The maximum solid solubilities of Cr in Tb2Co17, TbCo3, and TbCo2 are about 20.0, 8.2, and 7.9 at.%, respectively.