Atomic and Molecular Layer Deposition for Efficient Capacitive Deionization, Plasma Corrosion Protection and Stable High-Energy Lithium Ion Batteries

Atomic layer deposition (ALD) is a technique to deposit thin films with great precision. Molecular layer deposition (MLD), developed as an analog of ALD, is a technique to deposit organic polymer or hybrid organic-inorganic thin films with great precision. ALD and MLD techniques have played a major role in advancing many fields, such as in semiconductor fabrication, sensors, energy production and energy storage. In this dissertation I describe three research projects in which ALD or MLD thin films were developed for applications in water desalination, energy storage and semiconductor fabrication. One project investigated an ultrathin polyamide coating developed for the silicon anode in lithium-ion batteries. The coating, deposited via spatial molecular layer deposition (MLD), enhanced the structural integrity of the anode and permitted stable electrochemical cycling. In the second project thin-film sodium manganese oxide (NMO) was used as an electrode coating in capacitive deionization (CDI). CDI is an emerging electrochemical desalination technology that shows promise but suffers from capacity and efficiency limitations. An NMO coating on the cathode within a CDI device improved desalination capacity and efficiency. The focus of the third project was the development of ALD YF₃ and YOₓFᵧ thin films with a tunable composition to be deployed as plasma corrosion barriers. These new ALD chemistries have distinct properties and may interact differently with different reactive plasmas. With the high level of control over the composition of these films, it may be possible to tailor a protective coating for the type of reactive plasma used in each unique plasma chamber. These three projects highlight the versatility and value of ALD and MLD thin films.</p

Lipid-Modified Aminoglycoside Derivatives for In Vivo siRNA Delivery

Rationally designed siRNA delivery materials that are enabled by lipid-modified aminoglycosides are demonstrated. Leading materials identified are able to self-assemble with siRNA into well-defined nanoparticles and induce efficient gene knockdown both in vitro and in vivo. Histology studies and liver function tests reveal that no apparent toxicity is caused by these nanoparticles at doses over two orders of magnitude.Damon Runyon Cancer Research Foundation (DFS-#2050-10)Alnylam Pharmaceuticals (Firm)National Institutes of Health (U.S.) (grant EB000244)National Institutes of Health (U.S.) (grant 1-RO1-CA132091-03

Modular ‘Click-in-Emulsion’ Bone-Targeted Nanogels

A new class of nanogel demonstrates modular biodistribution and affinity for bone. Nanogels, ~70 nm in diameter and synthesized via an astoichiometric click-chemistry in-emulsion method, controllably display residual, free clickable functional groups. Functionalization with a bisphosphonate ligand results in significant binding to bone on the inner walls of marrow cavities, liver avoidance, and anti-osteoporotic effects.National Institutes of Health (U.S.) (RO1 DE016516)National Institutes of Health (U.S.) (R01 EB000244)Damon Runyon Cancer Research Foundation (DFS-#2050-10

Coating Solution for High-Voltage Cathode: AlF₃ Atomic Layer Deposition for Freestanding LiCoO₂ Electrodes with High Energy Density and Excellent Flexibility

Freestanding LiCoO₂/multiwall carbon nanotube/nanocellulose fibril (LCO-MWCNT-NCF) electrodes are fabricated by a vacuum filtration technique. The electrode has a high LCO loading of 20 mg/cm² with excellent flexibility, uniform material distribution, and low surface resistivity. When coated with 2 ALD cycles of AlF₃, LCO-MWCNT-NCF has a high specific capacity of 216 mAh/g at 4.7 V. The freestanding AlF₃-coated electrode preserves 75.7% of its initial capacity after 100 cycles and 70% after 160 cycles of charge discharge. In contrast, electrodes coated with 2 ALD cycles of Al₂O₃ cannot be cycled above 4.5 V. By elimination of the unnecessary weight of current collector, and increasing in the working voltage simultaneously, this freestanding LCO-MWCNT-NCF electrode can significantly improve the gravimetric and volumetric energy density of lithium ion batteries