Maxwell David Radin

Zapata Computing

The industrial manufacturing of chemicals consumes a significant amount of energy and raw materials. In principle, the development of new catalysts could greatly improve the efficiency of chemical production. However, the discovery of viable catalysts can be exceedingly challenging because it is difficult to know the efficacy of a candidate without...

Recent advances in quantum computing devices have brought attention to hybrid quantum-classical algorithms like the variational quantum eigensolver (VQE) as a potential route to practical quantum advantage in chemistry. However, it is not yet clear whether such algorithms, even in the absence of device error, could actually achieve quantum advantag...

Quantum chemistry and materials is one of the most promising applications of quantum computing. Yet much work is still to be done in matching industry-relevant problems in these areas with quantum algorithms that can solve them. Most previous efforts have carried out resource estimations for quantum algorithms run on large-scale fault-tolerant arch...

The ability of near-term quantum computers to represent classically-intractable quantum states has brought much interest in using such devices for estimating the ground and excited state energies of fermionic Hamiltonians. The usefulness of such near-term techniques, generally based on the Variational Quantum Eigensolver (VQE), however, is limited...

Recent advances in Noisy Intermediate-Scale Quantum (NISQ) devices have brought much attention to the potential of the Variational Quantum Eigensolver (VQE) and related techniques to provide practical quantum advantage in computational chemistry. However, it is not yet clear whether such algorithms, even in the absence of device error, could achiev...

Quantum simulation of chemistry and materials is predicted to be an important application for both near-term and fault-tolerant quantum devices. However, at present, developing and studying algorithms for these problems can be difficult due to the prohibitive amount of domain knowledge required in both the area of chemistry and quantum algorithms....

Large anharmonic vibrations often play a crucial role in dynamically stabilizing crystalline phases whose structures are unstable at low temperature. Although the average structure of such phases can be measured through diffraction experiments, their local structure remains a challenge to characterize and understand. Dynamically stabilized phases a...

Tin is an important component of a variety of promising anode and solid electrolyte chemistries for Li and Na ion batteries. Here we report on a first-principles investigation of phase stability and electronic structure in the Li-Sn-S ternary composition space, which hosts several compounds that can either serve as an anode or as a solid electrolyt...

The lithium-excess manganese oxides are a candidate cathode material for the next generation of Li-ion batteries because of their ability to reversibly intercalate more Li than traditional cathode materials. Although reversible oxidation of lattice oxygen has been proposed as the origin of this anomalous excess capacity, questions about the underly...

Oxygen participation, arising from increased transition metal-oxygen covalency during delithiation, is considered essential for the description of charge compensation in conventional layered oxides. The advent of high-resolution mapping of the O K-edge resonant inelastic X-ray scattering (RIXS) provides an opportunity to revisit the onset and exten...

One approach to increasing the capacity of Li-ion batteries is to expand the usable voltage range over which the battery is cycled by charging the cathode to higher voltages. Layered intercalation compounds commonly used as cathodes in Li-ion batteries, however, can become susceptible to irreversible structural changes at high states of charge due...

The practical utilization of energy densities near the theoretical limit for R3̅m layered oxide positive electrode materials is dependent on the stability of the electrochemical performance of these materials at or near full delithiation. In order to develop new chemistries and novel approaches towards the improvement of the electrochemical perform...

The crystal structure of the nickel battery positive electrode material, β-NiOOH, is analyzed through a joint approach involving NMR and FTIR spectroscopies, powder neutron diffraction and DFT calculations. The obtained results confirm that structural changes occur during the β-Ni(OH)2/β-NiOOH transformation leading to a metastable crystal structur...

The degrees of freedom associated with orbital, spin, and charge ordering can strongly affect the properties of many crystalline solids, including battery materials, high-temperature superconductors, and naturally occurring minerals. This work reports on the development of a computational framework to systematically explore the ordering of elec-tro...

One obstacle to realizing a practical, rechargeable magnesium-ion battery is the development of efficient Mg electrolytes. Electrolytes based on simple Mg(BH4)2 salts suffer from poor salt solubility and/or low conductivity, presumably due to strong ion pairing. Understanding the molecular-scale processes occurring in these electrolytes would aid i...

The performance of many technologies, such as Li- and Na-ion batteries as well as some 2D electronics, is dependent upon the reversibility of stacking-sequence-change phase transformations. However, the mechanisms by which such transformations lead to degradation are not well understood. This study explores lattice-invariant shear as a source of ir...

Although layered lithium oxides have become the cathode of choice for state-of-the-art Li-ion batteries, substantial gaps remain between the practical and theoretical energy densities. With the aim of supporting efforts to close this gap, this work reviews the fundamental operating mechanisms and challenges of Li intercalation in layered oxides, co...

The performance of Na-ion batteries is sensitive to the nature of cation ordering and phase transformations that occur within the intercalation compounds used as electrodes. In order to elucidate these effects in layered Na intercalation compounds, we have carried out a first-principles statistical mechanics study of Na ordering and stacking-sequen...

Many layered oxide and sulfide intercalation compounds used in secondary batteries undergo stacking-sequence-change phase transformations during (de)intercalation. However, the underlying reasons why different intercalants result in different stacking-sequence changes is not well understood. This work reports on high-throughput density functional t...

The performance of Li/O2 batteries is thought to be limited by charge transport through the solid Li2O2 discharge product. Prior studies suggest that electron tunneling is the main transport mechanism through thin, compact Li2O2 deposits. The present study employs a new continuum transport model to explore an alternative scenario, in which charge t...

A viable Li/O2 battery will require the development of stable electrolytes that do not continuously decompose during cell operation. Recent experiments suggest that reactions occurring at the interface between the liquid electrolyte and the solid lithium peroxide (Li2O2) discharge phase are a major contributor to these instabilities. To clarify the...

The performance of high-capacity Li/O-2 batteries is limited by the high overpotential associated with the oxygen evolution reaction (OER) during charging. These losses have been attributed to sluggish charge transport within the solid lithium peroxide (Li2O2) discharge phase. Recent experiments have shown that use of Co3O4-containing Li/O-2 electr...

Supercapacitors store energy via the formation of an electric double layer, which generates a strong electric field at the electrode-electrolyte interface. Unlike conventional metallic electrodes, graphene-derived materials suffer from a low electronic density of states (i.e., quantum capacitance), which limits their ability to redistribute charge...

Amorphous Li2O2 is investigated using first-principles “melt-and-quench” molecular dynamics and percolation theory.

The properties of the Li2O2 discharge phase are expected to impact strongly the performance of Li-air batteries. Although both crystalline Li2O2 (c-Li2O2) and amorphous Li2O2 (a-Li2O2) have been reported to form in Li-air cells, little is known regarding possible differences in charge and mass transport within these phases. To reveal these differen...

We report heat capacity, thermogravimetry and thermal diffusivity data for carbonized mesophase pitch coated LiFePO4 (LFP) cathodes. The results are compared with the thermophysical properties of a conventional LFP-based electrode having a poly (vinylene) difluoride (PVDF) binder and conductive carbon diluents. The measured heat capacity of LFP as...

Li-O2 batteries are a very attractive energy storage technology due to their high theoretical specific energy density. However, several critical challenges impede the development of a practical Li-O2 battery. One of these challenges is the sluggish transport of ions and/or electrons through the Li2O2 discharge product. The purpose of this work is t...

The mechanisms and efficiency of charge transport in lithium peroxide (Li2O2) are key factors in understanding the performance of non-aqueous Li-air batteries. Towards revealing these mechanisms, here we use first-principles calculations to predict the concentrations and mobilities of charge carriers and intrinsic defects in Li2O2 as a function of...

The surface properties of the Li 2 O 2 discharge phase are expected to impact strongly the capacity, rate capability, and rechargeability of Li-oxygen batteries. Prior calculations have suggested that the presence of half-metallic surface states in Li 2 O 2 may mitigate electrical passivation resulting from the growth of Li 2 O 2 , which is a bulk...

The thermodynamic stability and electronic structure of 40 surfaces of lithium peroxide (Li(2)O(2)) and lithium oxide (Li(2)O) were characterized using first-principles calculations. As these compounds constitute potential discharge products in Li-oxygen batteries, their surface properties are expected to play a key role in understanding electroche...

Of the many possible battery chemistries, the so-called "Li-air" system is noteworthy in that its theoretical capacity (˜5 kWh/kg, including mass of oxygen) exceeds that of any electrochemical system. Perhaps more importantly, the simplified composition of its air cathode -- involving only the inlet of oxygen from the atmosphere -- has the potentia...