Obrovac, Mark N.: Recent submissions
Now showing items 21-40 of 45
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Sintered polymeric binders for Li-ion battery alloy anodes
The cycling performance in lithium half cells of Si alloy electrodes with polyvinylidene fluoride or polyimide binders were evaluated after the electrodes were cured at temperatures below and above the binder carbonization ... -
Preparation of Low Surface Area Si-Alloy Anodes for Li-Ion Cells by Ball Milling
A new and simple 2-step milling technique is utilized to produce Si–Ti–N alloys with significantly reduced surface area compared to conventional ball milling, while still attaining a full amorphous active Si phase. Surface ... -
Si85Fe15Ox Alloy Anode Materials with High Thermal Stability for Lithium Ion Batteries
The synthesis, microstructure and electrochemical properties of ball milled Si85Fe15Ox alloys with different oxygen contents are investigated. These materials combine the features of Si-M alloys (low irreversible capacity) ... -
Isothermal Calorimetry Evaluation of Metallurgical Silicon as a Negative Electrode Material for Li-Ion Batteries
The structural evolution of Si during lithiation and delithiation is uniquely dependent on the cycling conditions and can show either reversible or path dependent behavior. In this paper, metallurgical Si (large crystalline ... -
Inorganic Compounds as Binders for Si-Alloy Anodes
The inorganic compounds, lithium polysilicate (Li2Si5O11), sodium polyphosphate ((NaPO3)n), and lithium phosphate monobasic (H2LiPO4) were investigated as the sole binders in Si-alloy and graphite electrodes for Li cells. ... -
LiF as an Alloy Component or Slurry Additive in Si-Alloy Anodes
Electrolyte additives are commonly used to improve electrochemical performance in Li-ion cells. The use of solids as electrolyte additives is far less common. Here, Si40'(FeSi2)(60−x)'(LiF)(x)' (' = volume percent) alloys ... -
All-Dry Synthesis of Single Crystal NMC Cathode Materials for Li-Ion Batteries
Single crystal (SC) cathode materials with a layered structure are considered to be state-of-the-art for lithium ion batteries. However, their production involves many steps and can produce large amounts of wastewater. ... -
Lithium Insertion in Nanostructured Si1-xTix Alloys
Nanostructured Si1-xTix alloys (0 ≤ x ≤ 0.3) prepared by ball milling were studied as negative electrode materials in Li cells. The alloys comprised a nanocrystalline andamorphousSiphaseandananocrystallineC49TiSi2 phase. ... -
Rapid mechanochemical synthesis of amorphous alloys
A rapid method for preparing amorphous alloys has been developed utilizing a SPEX high energy ball mill. Parameters such as ball size, mass of balls and milling time, were systematically optimized to prepare amorphous ... -
Electrochemical Activity of Nano-NiSi2 in Li Cells
Crystalline and nanocrystalline NiSi2 were studied as negative electrode materials in Li cells. Crystalline NiSi2 was found to be inactive toward lithiation/delithiation. However, it was found that NiSi2 becomes active ... -
Honeycomb Compound Na3Ni2BiO6 as Positive Electrode Material in Na Cells
Honeycomb compound Na3Ni2BiO6 was synthesized and studied as positive electrode material in sodium cells for the first time. This material exhibits a reversible capacity of ∼80 mAh/g and an average voltage of ∼3.1 V, ... -
Phenolic Resin as an Inexpensive High Performance Binder for Li-Ion Battery Alloy Negative Electrodes
Phenolic resin was evaluated as a binder material for Li-ion battery negative electrodes containing Si-based alloys. Phenolic resin was found to have a large first lithiation capacity of about 1200 mAh/g, which is suspected ... -
Electrochemistry of CuxSi1−x Alloys in Li Cells
The structure and electrochemistry in lithium cells of sputtered thin films and ball milled alloys in the Cu-Si system (0 ≤ x ≤ 0.60 in CuxSi1−x) were investigated. Both thin films and ball milled Cu-Si alloys showed the ... -
The Electrochemical Reaction Mechanism of Tin Phosphide with Sodium
The sodiation mechanism of Sn4P3 was studied by ex-situ X-ray diffraction and Mössbauer effect spectroscopy. These results show that Sn4P3 is initially amorphized during sodiation, and suggest that upon further sodiation ... -
Electrochemistry of Catalytically Graphitized Ball Milled Carbon in Li Batteries
High carbon Fe-C composites with starting concentrations of 10, 20, 30, and 40 wt% Fe (2.3 - 12.5 atomic % Fe) were prepared by ball milling followed by annealing. Increasing the Fe concentration and annealing temperature ... -
The Electrochemical Behavior of Polyimide Binders in Li and Na Cells
The electrochemistry of aromatic and aliphatic polyimide binders was characterized in composite coatings for Li-ion and Na-ion battery negative electrodes. Aromatic polyimide was found to have a large first lithiation ... -
Li15Si4 Formation in Silicon Thin Film Negative Electrodes
The conditions for Li15Si4 formation in Si thin film negative electrodes was studied during charge and discharge cycling in lithium cells. It was found that Li15Si4 formation can be suppressed during cycling of Si thin ... -
NixSi1-x Alloys Prepared by Mechanical Milling as Negative Electrode Materials for Lithium Ion Batteries
NixSi1-x (0 ≤ x ≤ 0.5, x = 0.05) alloys were prepared by ball milling and studied as anode materials for lithium ion batteries. Nanocrystalline Si/NiSi2 phases were formed for x ≤ 0.25. The NiSi phase was observed for ... -
Combinatorial Study of the Si-Sn-O System as Negative Electrode Materials in Li-Ion Cells
SixSnyO1-x-y films with 0.45 < x < 0.80, 0.05 < y < 0.35, and 0.05 < (1-x-y) < 0.40 have been prepared using a magnetron sputtering method. All compositions had an amorphous structure and good capacity retention. Reversible ... -
The Electrochemistry of Amorphous Si-B Thin Film Electrodes in Li Cells
Abstract Si1-xBx thin films of 0.071 ≤ x ≤ 0.950 have been synthesized using combinational sputtering. All Si1-xBx film compositions had a highly amorphous structure consisting of amorphous Si and B phases, as characterized ...