Dr Jialong Wang

Herein we describe a modified Swagelok electrochemical cell for characterizing individual electrode behavior as part of full cell operation, including individual electrode potentials and dissolution phenomena. The case study presented is that of the non-aqueous Li-LiMn2O4 system. Outcomes from the work include characterization of lithium negative electrode potential variation with applied current, lithium corrosion and passivation in the electrolyte, and LiMn2O4 dissolution with cycling. It is also demonstrated that Mn(III) is the dissolution product. Application of the technique to other systems, including electrode materials and electrolytes, is discussed.

A few-layer graphene (FLG) composite material was synthesized using a rich reservoir and low-cost coal under the microwave-assisted catalytic graphitization process. X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to evaluate the properties of the FLG sample. A well-developed microstructure and higher graphitization degree were achieved under microwave heating at 1300¿ C using the S5% dual (Fe-Ni) catalyst for 20 min. In addition, the synthesized FLG sample encompassed the Raman spectrum 2D band at 2700 cm-1, which showed the existence of a few-layer graphene structure. The high-resolution TEM (transmission electron microscopy) image investigation of the S5% Fe-Ni sample confirmed that the fabricated FLG material consisted of two to seven graphitic layers, promoting the fast lithium-ion diffusion into the inner surface. The S5% Fe-Ni composite material delivered a high reversible capacity of 287.91 mAhg-1 at 0.1 C with a higher Coulombic efficiency of 99.9%. In contrast, the single catalyst of S10% Fe contained a reversible capacity of 260.13 mAhg-1 at 0.1 C with 97.96% Coulombic efficiency. Furthermore, the dual catalyst-loaded FLG sample demonstrated a high capacity¿up to 95% of the initial reversible capacity retention¿after 100 cycles. This study revealed the potential feasibility of producing FLG materials from bituminous coal used in a broad range as anode materials for lithium-ion batteries (LIBs).