Research
All-solid-state batteries
Under harsh or abnormal operating conditions, current lithium-ion batteries (LIBs) with flammable liquid electrolytes suffer from significant performance degradation and are at risk of catching fire or exploding. All-solid-state batteries (ASSBs) constitute energy storage technology that can overcome the safety and reliability issues of LIBs. Furthermore, a bipolar design of ASSBs has the potential to increase the energy density, while reducing material and fabrication costs.
Li-metal batteries
The Li-metal anode has attracted much attention as an alternative to graphite because it can improve the energy density of batteries. However, its commercial viability is hindered by the uncontrollable growth of Li dendrites and large volume changes during repeated cycling. Considerable effort is being made to mitigate the dendritic growth of metallic Li, including metallic Li storage in three-dimensional (3D) framework electrodes. The 3D framework electrodes with large surface areas and high porosities have the ability to confine metallic Li within their porous architectures, which should result in reduced local (effective) current densities and increased tolerance to volume variation.
Advanced Li-ion batteries
Charging time is regarded as a critical factor influencing customer willingness to adopt electric vehicles; however, the realization of fast-charging LIBs with long cycle lifetimes is hindered by the uncontrollable plating of metallic Li on the graphite anode during high-rate charging. In addition to inducing a significant capacity loss during high-rate cycling, dendritic Li plating can cause short-circuiting and thus result in LIB ignition or even explosion. Furthermore, extensive efforts have been devoted to design and develop advanced cathode materials with high capacity and high operating voltages.
Metal-gas batteries
In recent years, there has been a strong demand for advanced rechargeable battery systems with high energy storage capability. Among the various energy storage technologies under development, the metal-air battery, in which a metal anode (Li, Zn, Al, etc.) is coupled with an air-breathing porous cathode, delivers much higher specific energy compared to conventional battery chemistries such as lithium-ion batteries.
Electrochemical analysis and simulations
The charging-discharging processes of batteries involve multiple physical and electrochemical reactions at multi-scales. AC impedance spectroscopy provides a useful tool to characterize and deconvolute complicated reaction processes in batteries. Furthermore, electrochemical-mechanical simulations help understand detailed mechanisms at particle-, electrode-, and cell-levels and provide insights into practical guidelines for designing advanced batteries.
