Amy C Marschilok

Heat-Treatment of Synthetic Graphite under Argon and Effect on Li-Ion Electrochemistry

The novel use of heat-treatment in flowing Ar to systematically affect particle and crystallite dimensions of synthetic graphite LK-702 is reported. Samples were characterized by percent mass loss, X-ray powder diffraction, scanning electron microscopy, Brunauer-Emmett-Teller (BET) surface area, and methylene blue adsorption surface area measurements. The treated graphites were studied as possible electrode materials for Li-ion cells. The BET and methylene blue surface areas increased for treatment times up to 48 h, then remained constant. For times up to 48 h, Ar treatment was demonstrated to break apart larger graphite particles, narrowing the particle size distribution. The irreversible capacity of the graphite decreased substantially with increased Ar treatment time, while the reversible capacity remained unchanged.

Synthesis and Electrochemistry of Nanocrystalline Iron and Manganese Oxide Materials

In this presentation, novel low temperature, scalable methods will be discussed for preparation of two promising battery materials, magnetite and silver hollandite. Synthetic strategies for crystallographic control will be discussed, along with resulting impact of molecular architecture and composition on electrochemistry. This work will contribute to materials advances in the development of environmentally sustainable materials for new battery technologies.

Final Technical Report on DE-SC00002460 [Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V]

Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V were investigated under this project. These metal centers are the focus of this research as they have high earth abundance and have each shown success as cathode materials in lithium batteries. Silver ion, Ag{sup +}, was initially selected as the displacement material as reduction of this center should result in increased conductivity as Ag{sup 0} metal particles are formed in-situ upon electrochemical reduction. The in-situ formation of metal nanoparticles upon electrochemical reduction has been previously noted, and more recently, we have investigated the resulting increase in conductivity. Layered materials as well as materials with tunnel or channel type structures were selected. Layered materials are of interest as they can provide 2-dimensional ion mobility. Tunnel or channel structures are also of interest as they provide a rigid framework that should remain stable over many discharge/charge cycles. We describe some examples of materials we have synthesized that demonstrate promising electrochemistry.

In-Situ Generation of Electrically Conductive Nanoparticles in Bimetallic Phosphate Materials for High Power Lithium Batteries

Polyanion compounds are receiving significant attention as materials for energy storage applications, most generally with compositions such as LixMyOz and LiwMxPyOz, where M = Fe, Mn, or V. Due to the opportunity to transfer multiple electrons per M formula unit, these materials can provide high capacities in lithium based electrochemical cells. Vanadium oxide based batteries have exhibited widespread utility for a variety of uses, including demanding specialty applications.(1) For example, silver vanadium oxide has dominated the implantable cardiac defibrillator market over the past 25+ years due to its high capacity, characteristic voltage curve, and high power output.(2, 3)