Research Sponsors and Collaborators:

Research Interests

1. Precisely controllable nanosynthesis using atomic and molecular layer deposition (ALD & MLD)

 Atomic/Molecular Layer Deposition (ALD/MLD) are powerful techniques in developing novel nanostructured materials with unrivaled precision and controllability, suitable for almost any organic and inorganic materials. Consequently, they are providing new solutions in many applications from semiconductors to catalysis, new energies, surface engineering, metamaterials, and biomedical areas. Our research features the utilization of in situ techniques (such as quadrupole mass spectroscopy, quartz crystal microbalance, and Fourier infrared spectroscopy) to explore new ALD/MLD processes for novel inorganic, organic, and hybrid materials. This study has great potential in providing solutions to the above-mentioned applications.

 Our group focuses on using ALD/MLD to fabricate new nanophase materials for various energy-storage battery systems as anodes, cathodes,  solid-state electrolytes, and surface coating materials.

 2. Development of alkali metal anodes via ALD/MLD

Alkali metals (lithium, sodium, and potassium) are promising as anodes in emerging rechargeable batteries, ascribed to their high capacity or abundance. Two commonly experienced issues, however, have hindered them from commercialization: the dendritic growth of alkali metals during plating and the formation of solid electrolyte interphase due to contact with liquid electrolytes. Many technical strategies have been developed for addressing these two issues in the past decades. Among them, atomic and molecular layer deposition (ALD & MLD) have been drawing more and more efforts, owing to a series of their unique capabilities. ALD and MLD enable a variety of inorganic, organic, and even inorganic-organic hybrid materials, featuring accurate nanoscale controllability, low process temperature, and extremely uniform and conformal coverage. Consequently, ALD and MLD have paved a novel route for tackling the issues of alkali metal anodes. Our research aims at developing feasible strategies to resolve existing technical issues in various battery systems including lithium-metal oxide (e.g., Li-NMC) batteries,  lithium-sulfur (Li-S) batteries, lithium-air (Li-O₂) batteries, sodium-based batteries, and manganese-based batteries.

3. Development of high-nickel cathodes via ALD/MLD

Currently, there has an ever-growing interest in layered LiNi_xMn_yCo_zO₂ (NMCs, x + y + z = 1) cathode materials for lithium-ion batteries (LIBs) and lithium metal batteries (LMBs), due to their low cost and high capacity. However, they still suffer from a series of issues, such as Li/Ni cation mixing, irreversible phase transition, and transition metal dissolution. These issues result in severe capacity degradation and limited cyclability of NMCs. Recently, atomic and molecular layer deposition (ALD and MLD) have emerged as a novel tool to tackle these issues, featuring their unique capabilities to fine-tailor NMCs’ surfaces for stable interfaces and improved electrochemical performance in LIBs and LMBs. 

Our research focuses on developing novel nanoscale coatings via ALD and MLD to address the issues of NMCs. Our recent breakthrough in sulfide coatings for the first time opens a brand-new research area and hopefully remarkably mitigate the issues faced by NMCs.  We are also devoting to development of superionically conductive coatings. Particularly, we combine ALD and MLD to develop novel hybrid coatings for NMCs.

4. Development of solid-state electrolytes via ALD/MLD

Solid-state electrolytes (SEs) can be inorganic (iSEs), polymeric (pSEs), and hybrid (hSEs). Currently there has an ever-growing interest in solid-state electrolytes, given the fact that traditional organic liquid electrolytes (oLEs) have become a major limiting factor for next-generation high-energy lithium-ion batteries (LIBs) and beyond. In this context, SEs are currently undergoing an intensive investigation in order to accomplish solid-state batteries (SSBs) with reliable safety, longer lifetime, lower cost, and higher energy and power density. To date there have been many methods developed for synthesizing iSEs. Among them, atomic layer deposition (ALD) has recently emerged as a new technique with exceptional capabilities to enable atomic-scale rational designs, in situ uniform and conformal growth, low process temperature, and high operational flexibility, and large variety of material choices. Additionally, MLD is emerging as a new method for growing ionically conductive pSEs. Combining ALD and MLD, particularly, hSEs are often very desirable. we are pioneers in exploring SEs to replace traditional oLEs, and thereby ultimately resolving battery safety issues and the interfacial instability due to the direct contact of electrodes with oLEs.

 Research Capabilities

Toxic gases (H2S and NH3) used as precursors for ALD/MLD

ALD-1: An integrated system combining an atomic/molecular layer deposition system with a glove box

Battery Cycler 1

Battery Cycler 2

Temperature Chamber

High Temperature Furnace & Low Temperature Oven

CVD Tube Furnace & Coin Cell Crimper

In Situ Quartz Crystal Microbalance (QCM)

Fume Hood

Office

User Facilities for Materials Characterization