129 research outputs found
Recommended from our members
AdvancingIn situAnalytical Electron Microscopy for Probing Dynamic Nano-Scale Solid State Electrochemistry
Recommended from our members
Future energy, fuel cells, and solid-oxide fuel-cell technology
According to the US Department of Energy’s Energy Infomation Administration (EIA) (International Energy Outlook 2017), world energy consumption will increase 28% between 2015 and 2040, rising from 575 quadrillion Btu (∼606 quadrillion kJ) in 2015 to 736 quadrillion Btu (∼776 quadrillion kJ) in 2040. EIA predicts increases in consumption for all energy sources (excluding coal, which is estimated to remain flat)—fossil (petroleum and other liquids, natural gas), renewables (solar, wind, hydropower), and nuclear. Although renewables are the world’s fastest growing form of energy, fossil fuels are expected to continue to supply more than three-quarters of the energy used worldwide. Among the various fossil fuels, natural gas is the fastest growing, with a projected increase of 43% from 2015 to 2040. As the use of fossil fuels increases, the EIA projects world energy-related carbon dioxide emission to grow from ∼34 billion metric tons in 2015 to ∼40 billion metric tonnes in 2040 (an average 0.6% increase per year)
Investigation on Aluminum-Based Amorphous Metallic Glass as New Anode Material in Lithium Ion Batteries
Aluminum based amorphous metallic glass powders were produced and tested as the anode materials for the lithium ion rechargeable batteries. Ground Al₈₀Ni₁₀La₁₀ was found to have a low first cycle capacity of about 100 Ah/Kg. The considerable amount of intermetallic formed in the amorphous glass makes the aluminum inactive towards the lithium. The ball milled Al₈₈Ni₉Y₃ powders contain pure aluminum crystalline particles in the amorphous matrix and have first cycle capacity of about 500 Ah/Kg. Nevertheless, polarization was caused by oxidation introduced by the ball-milling process. The electrochemical performances of these amorphous metallic glasses need to be further investigated. Their full lithium insertion capacities cannot be confirmed until the compositions and particle size inside the metallic glass anodes, the conformation of the electrodes and the mechanical milling processes are optimized.Singapore-MIT Alliance (SMA
Synthesis, electrochemistry and First Principles Calculation studies of layered Li-Ni-Ti-O compounds
New layered cathode materials, Li₀.₉Ni₀.₄₅Ti₀.₅₅O₂, were synthesized by means of ion-exchange from Na₀.₉Ni₀.₄₅Ti₀.₅₅O₂. The degree of cation disordering in the material depends critically on the synthesis conditions. Longer times and higher temperatures in the ion-exchange process induced more cation disordering. However, the partially disordered phase showed better capacity retention than the least disordered phase. First principles calculations indicated this could be attributed to the migration of Ti⁺⁴ into the Li layer during the electrochemical testing, which seems to depend sensitively on the Ni⁺² -Ti⁺⁴ configuration in the transition metal layer. The poor conductivity of this material could also be the reason for its low specific capacity according to the Density of States (DOS) obtained from first principles calculations indicating that only Ni participates in the electronic conductivity.Singapore-MIT Alliance (SMA
Local structure of glassy lithium phosphorus oxynitride thin films: a combined experimental and ab initio approach
Lithium phosphorus oxynitride (LiPON) is an amorphous solid-state lithium ion
conductor displaying exemplary cyclability against lithium metal anodes. There
is no definitive explanation for this stability due to the limited
understanding of the structure of LiPON. We provide a structural model of
RF-sputtered LiPON via experimental and computational spectroscopic methods.
Information about the short-range structure results from 1D and 2D solid-state
nuclear magnetic resonance experiments investigating chemical shift anisotropy
and dipolar interactions. These results are compared with first principles
chemical shielding calculations of Li-P-O/N crystals and ab initio molecular
dynamics-generated amorphous LiPON models to unequivocally identify the glassy
structure as primarily isolated phosphate monomers with N incorporated in both
apical and as bridging sites in phosphate dimers. Structural results suggest
LiPON's stability is a result of its glassy character. Free-standing LiPON
films are produced that exhibit a high degree of flexibility highlighting the
unique mechanical properties of glassy materials
Disorder Dynamics in Battery Nanoparticles During Phase Transitions Revealed by Operando Single-Particle Diffraction
Structural and ion-ordering phase transitions limit the viability of
sodium-ion intercalation materials in grid scale battery storage by reducing
their lifetime. However, the combination of phenomena in nanoparticulate
electrodes creates complex behavior that is difficult to investigate,
especially on the single nanoparticle scale under operating conditions. In this
work, operando single-particle x-ray diffraction (oSP-XRD) is used to observe
single-particle rotation, interlayer spacing, and layer misorientation in a
functional sodium-ion battery. oSP-XRD is applied to
Na[NiMn]O, an archetypal P2-type sodium-ion
positive electrode material with the notorious P2-O2 phase transition induced
by sodium (de)intercalation. It is found that during sodium extraction, the
misorientation of crystalline layers inside individual particles increases
before the layers suddenly align just prior to the P2-O2 transition. The
increase in the long-range order coincides with an additional voltage plateau
signifying a phase transition prior to the P2-O2 transition. To explain the
layer alignment, a model for the phase evolution is proposed that includes a
transition from localized to correlated Jahn-Teller distortions. The model is
anticipated to guide further characterization and engineering of sodium-ion
intercalation materials with P2-O2 type transitions. oSP-XRD therefore opens a
powerful avenue for revealing complex phase behavior in heterogeneous
nanoparticulate systems.Comment: 23 pages, 4 main figures, 9 supplemental figure
Recommended from our members
High-Efficiency Lithium-Metal Anode Enabled by Liquefied Gas Electrolytes
Quantifying Inactive Lithium in Lithium Metal Batteries
Inactive lithium (Li) formation is the immediate cause of capacity loss and
catastrophic failure of Li metal batteries. However, the chemical component and
the atomic level structure of inactive Li have rarely been studied due to the
lack of effective diagnosis tools to accurately differentiate and quantify Li+
in solid electrolyte interphase (SEI) components and the electrically isolated
unreacted metallic Li0, which together comprise the inactive Li. Here, by
introducing a new analytical method, Titration Gas Chromatography (TGC), we can
accurately quantify the contribution from metallic Li0 to the total amount of
inactive Li. We uncover that the Li0, rather than the electrochemically formed
SEI, dominates the inactive Li and capacity loss. Using cryogenic electron
microscopies to further study the microstructure and nanostructure of inactive
Li, we find that the Li0 is surrounded by insulating SEI, losing the electronic
conductive pathway to the bulk electrode. Coupling the measurements of the Li0
global content to observations of its local atomic structure, we reveal the
formation mechanism of inactive Li in different types of electrolytes, and
identify the true underlying cause of low Coulombic efficiency in Li metal
deposition and stripping. We ultimately propose strategies to enable the highly
efficient Li deposition and stripping to enable Li metal anode for next
generation high energy batteries
- …