Xiujian Zhu

Room-Temperature Mechanosynthesis of Ni3S2 as Cathode Material for Rechargeable Lithium Polymer Batteries

The formation of Ni 3 S 2 was realized by mechanical alloying with metallic nickel and sulfur powder as precursors. The products were characterized by X-ray diffraction, thermoanalysis, and scanning electron microscopy. Electrochemical properties of Li/P(EO) 20 Li(CF 3 SO 2 ) 2 N-10 wt % γ-LiAlO 2 /Ni 3 S 2 cells were also presented. The initial discharge capacity of Ni 3 S 2 was 304 mAh g -1 , with a platform at about 1.4 V vs Li/Li + . A capacity fading rate of 0.5% per cycle was achieved within 100 cycles. The charge-discharge mechanism of Ni 3 S 2 was implied by the analysis of the charge-discharge potential profiles, the cyclic voltammetry traces, and the ex situ XRD patterns of the Ni 3 S 2 cathode.

Synthesis and the improved high-rate performance of LiMn2O4/Ag composite cathode for lithium-ion batteries

The LiMn 2 O 4 /Ag composite has been prepared by a chemical deposition of silver particles. Well dispersed and nanosized silver particles in the composites were realized by careful control of the preparation conditions. The experimental results showed that the 6.3 wt % Ag in the composite obviously reduced the impedance of the precursor and the polarization of the cathode/electrolyte interface in the cell and effectively improved the high rate cycling performance of LiMn 2 O 4 . The reversible capacity after 50 cycles remained at 103.2 mAh/g with capacity loss of 10.57% compared to the first cycle even at the charge-discharge rate as high as 10C.