Research

The growing demand for Li-ion batteries in electric and hybrid electric vehicles has led to a significant increase in the volume of new and end-of-life Li-ion batteries. Consequently, there are critical concerns regarding how to manage spent Li-ion batteries and how to secure uninterrupted supplies of valuable battery raw materials such as cobalt, nickel, and lithium. If end-of-life cathode materials, which contains substantial amounts of Co, Ni, and Li, can be reused for manufacturing new battery cells, they can be considered as highly enriched ore, keeping uninterrupted supplies of raw battery materials.

Our research group focuses on developing a scalable, innovative, direct Li-ion recycling process to recover spent cathode materials in directly reusable forms. We collaborated with Michigan Technological University (MTU, Dr. Lei Pan) to develop froth-flotation-based liberation/separation technique. Current efforts focus on fundamental investigation of cathode regeneration through different forms of delithiated cathode materials.

Degradation of Li-ion batteries is caused by a large number of physical and chemical mechanisms, which are closely coupled to one another. Our research lab aims to improve current understanding of degradation mechanisms of various battery materials and develop effective strategies to prevent the degradation phenomena.

Our recent works have identified the key degradation mechanisms of BP-based anode materials using a variety of characterization tools and showed how the degradation can be suppressed by material design. Currently, our research group focuses on developing in-operando characterization techniques to monitor degradation phenomena occurring in various types of battery materials and systems.

Conventional liquid electrolytes used in typical Li-ion batteries are highly reactive and flammable, which not only raises a safety concern but also limits the implementation of high voltage cathode materials and Li metal anode in electric vehicles. All-solid-state batteries – a new battery design that uses all solid components – have gain attention in recent years because of their potentials for holding much more energy while simultaneously avoiding the safety challenges of the liquid electrolyte-based counterparts. One of the main challenges of all-solid-state-batteries is chemical and mechanical instability of electrode/electrolyte interfaces, including Li dendrite growth, formation of an undesirable interphase layer, and micro/nano-cracks.

Our research group aims to unveiling interfacial degradation/failure mechanisms of all-solid-state-batteries using both experimental and computational approaches. In collaboration with Dr. Likun Zhu group at IUPUI, we have utilized a single particle-based in-situ characterization setup using focused ion beam-scanning electron microscope to fundamentally understand the physical and chemical changes at various electrode/solid electrolyte interfaces. We have also developed single particle and microstructure-based models to better understand the mechanical failure behavior of electrode/solid electrolyte interfaces at various conditions.

The development of next-generation battery materials enabling cell energy densities higher than 350 Wh/kg and 750 Wh/L is required to realize long-range electric vehicles. Our research lab aims to explore various synthesis approaches to design and develop promising conversion-type cathode as well as conversion/alloying-type anode materials that could be implemented in the next-generation of Li-ion batteries.

Our recent works have demonstrated how black phosphorus (BP)-based anode materials can be designed in different synthetic routes to achieve higher capacity, longer cycle life, and excellent rate capability.