Lecture: Magnesium as structural and energy storage material
Speaker:Dr. Muhammad Rashad
Time: 15:00 pm, Oct. 20th, 2018
Location:  210 meeting room, MSE building

Biography:
Dr. Muhammad Rashad is a PIFI-CAS Fellow at Dalian Institute of Chemical Physics, Chinese Academy of Sciences. He received his Ph.D. degree in Materials Science and Engineering from Chongqing University in 2014. He worked at Chongqing University as a postdoctoral research fellowship from 2014 to 2016. Currently he is working in Energy Storage Division at Dalian Institute of Chemical Physics. His research focuses on Magnesium composite design and synthesis of functional nanomaterials, graphene and other 2D materials for energy storage devices (Mg Ion Batteries). He has published 37 peer-reviewed articles and one book chapter since 2013. His work has been cited 970 times with h-index 16. He is the reviewer of several SCI journals and has been honored with several distinctions & awards.

Abstract:
The world is facing energy crisis and lightweight materials have gained prodigious research consideration to reduce the fuel consumption in automotive and aviation industry. Among light materials, magnesium and its alloys have been regarded as ideal structural materials due to their low density, high specific strength and damping properties. Despite offering many fascinating advantages over conventional metals, magnesium is facing numerous challenges which are currently hindering their use at commercial scale. In order to further improve mechanical strength of magnesium alloys, the magnesium composites and conventional thermomechanical process (i.e. hot extrusion, hot rolling, and forging) have been developed to achieve fine grains and uniformly dispersed reinforcement particles i.e. SiC, Al2O3, TiO2, and carbon nanotubes (CNTs).

The two dimensional graphene has become one of the most extensively investigated allotropes of carbon in recent years. [1] Graphene can be used as reinforcement to enhance the mechanical strength of polymers matrices. We were the first to employ graphene nanoplatelets (GNPs) as the reinforcement to enhance the mechanical strength of pure magnesium and aluminum matrices. The synthesized composites exhibited improved mechanical properties including hardness, tensile, compression and elongations.  To further boost up the potential of GNPs, metallic particles such as Al, Cu, and Ti were employed along with GNPs as hybrid reinforcements. Metallic particles not only contribute to the strength but also act as bridge between GNP and matrix. Furthermore, synergetic effect of GNP and CNTs, effect of carbon reinforcements (GNPs, CNTs) on growth of intermetallic phases, interface, and grain refinements were studied in magnesium alloys. Experimental results revealed that GNPs contribute to the strength of magnesium alloys at both room temperature and high temperatures. Besides, the electrochemical properties of GNPs based magnesium composites were also studied to examine the corrosion resistances. These strategies to combine the different properties enhancing factors in magnesium alloys will bring the realization of these composites in broad markets.

On the other hand, potentially safe and economically feasible rechargeable magnesium ion batteries (MIBs) have attracted tremendous research attention as an alternative to high cost and unsafe lithium ion batteries (LIBs). Thus, many efforts have been made on new electrode materials and electrolytes that can bring the realization of these devices. Herein, we have synthesized different cathode materials (such as vanadium oxides, manganese oxides, polyanion materials, and bio-waste derived activated carbon etc.) that can accommodate electroplating of Mg2+ ions. The synthesized nanostructured materials exhibited extraordinary performances as the cathode for MIBs with long cyclic stability and excellent rate capability. [2,3] Our findings shows that low diffusion rate of Mg2+, low reversibility, high polarization was suppressed in the rationally designed hybrid electrolytes and electrochemical performance of cathodes were boosted two to five times. These studies laid down a pathway for the synthesis of potentially safe, light, and inexpensive Mg energy storage system with great reversibility to replace conventional LIBs. Furthermore, newly synthesized bio-waste derived activated carbons were also tested for conventional Li+, Na+, and K+ ion batteries.

References:
1.H. Wang, X.Z. Yuan, et al., Advances in Colloid & Interface Science, 221 (2015) 41–59.
2.M. Rashad, H. Zhang, M. Asif, et al., ACS Applied Materials & Interfaces, 10 (5) (2018) 4757-4766.
3.M. Asif, M. Rashad, et al., Materials Today Energy 10 (2018) 108-117.