New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments in the discovery of nanoelectrolytes and nanoelectrodes for lithium batteries, fuel cells and supercapacitors. The advantages and disadvantages of the nanoscale in materials design for such devices are highlighted.

https://img62.chem17.com/1/20140715/635410323829886334962.pdf

Nanostructured materials for advanced energy conversion and storage devices

In the previous paper Ralph Brodd and Martin Winter described the different kinds of batteries and fuel cells. In this paper I will describe lithium batteries in more detail, building an overall foundation for the papers that follow which describe specific components in some depth and usually with an emphasis on the materials behavior. The lithium battery industry is undergoing rapid expansion, now representing the largest segment of the portable battery industry and dominating the computer, cell phone, and camera power source industry. However, the present secondary batteries use expensive components, which are not in sufficient supply to allow the industry to grow at the same rate in the next decade. Moreover, the safety of the system is questionable for the large-scale batteries needed for hybrid electric vehicles (HEV). Another battery need is for a high-power system that can be used for power tools, where only the environmentally hazardous Ni/ Cd battery presently meets the requirements. A battery is a transducer that converts chemical energy into electrical energy and vice versa. It contains an anode, a cathode, and an electrolyte. The anode, in the case of a lithium battery, is the source of lithium ions. The cathode is the sink for the lithium ions and is chosen to optimize a number of parameters, discussed below. The electrolyte provides for the separation of ionic transport and electronic transport, and in a perfect battery the lithium ion transport number will be unity in the electrolyte. The cell potential is determined by the difference between the chemical potential of the lithium in the anode and cathode, ∆G ) -EF. As noted above, the lithium ions flow through the electrolyte whereas the electrons generated from the reaction, Li ) Li+ + e-, go through the external circuit to do work. Thus, the electrode system must allow for the flow of both lithium ions and electrons. That is, it must be both a good ionic conductor and an electronic conductor. As discussed below, many electrochemically active materials are not good electronic conductors, so it is necessary to add an electronically conductive material such as carbon * To whom correspondence should be addressed. Phone and fax: (607) 777-4623. E-mail: stanwhit@binghamton.edu. 4271 Chem. Rev. 2004, 104, 4271−4301

http://www.chemie.uni-regensburg.de/Anorganische_Chemie/Vortrag/StudentenWS06-07/Vortrag_Amereller.pdf

Lithium Batteries and Cathode Materials

Li-ion battery materials: present and future

Research Development on Sodium-Ion Batteries

Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end.

https://hal.archives-ouvertes.fr/hal-01171774/document

Pseudocapacitive oxide materials for high-rate electrochemical energy storage

Materials with the olivine structure form an important class of rechargeable battery cathodes. Using first-principles methods, activation barriers to Li ion motion are calculated and an estimate for Li diffusion constants, in the absence of electrical conductivity constraints, is made. Materials with Fe, Co, Ni are considered. Li diffuses through one-dimensional channels with high energy barriers to cross between the channels. Without electrical conductivity limitations the intrinsic Li diffusivity is high. © 2003 The Electrochemical Society. All rights reserved.

Li conductivity in lix mpo 4 ( m = mn , fe , co , ni ) olivine materials

In this work, the phase diagram of ${\mathrm{Li}}_{x}{\mathrm{CoO}}_{2}$ is calculated from first principles for x ranging from 0 to 1. Our calculations indicate that there is a tendency for Li ordering at $x=\frac{1}{2}$ in agreement with experiment [J. N. Reimers and J. R. Dahn, J. Electrochem. Soc. 139, 2091 (1992)]. At low Li concentration, we find that a staged compound is stable in which the Li ions selectively segregate to every other Li plane leaving the remaining Li planes vacant. We do not find the two-phase region observed at high Li concentration and speculate that this two-phase region is caused by the metal-insulator transition that occurs at concentrations slightly below $x=1.$

First-principles investigation of phase stability in Li x CoO 2

Many multicomponent materials exhibit significant configurational disorder Diffusing ions in such materials migrate along a network of sites that have different energies and that are separated by configuration dependent activation barriers We describe a formalism that enables a first-principles calculation of the diffusion coefficient in solids exhibiting configurational disorder The formalism involves the implementation of a local cluster expansion to describe the configuration dependence of activation barriers The local cluster expansion serves as a link between accurate first-principles calculations of the activation barriers and kinetic Monte Carlo simulations By introducing a kinetically resolved activation barrier, we show that a cluster expansion for the thermodynamics of ionic disorder can be combined with a local cluster expansion to obtain the activation barrier for migration in any configuration This ensures that in kinetic Monte Carlo simulations, detailed balance is maintained at all times and kinetic quantities can be calculated in a properly equilibrated thermodynamic state As an example, we apply this formalism for an investigation of lithium diffusion in ${\mathrm{Li}}_{x}{\mathrm{CoO}}_{2}$ A study of the activation barriers in ${\mathrm{Li}}_{x}{\mathrm{CoO}}_{x}$ within the local density approximation shows that the migration mechanism and activation barriers depend strongly on the local lithium-vacancy arrangement around the migrating lithium ion By parametrizing the activation barriers with a local cluster expansion and applying it in kinetic Monte Carlo simulations, we predict that lithium diffusion in layered ${\mathrm{Li}}_{x}{\mathrm{CoO}}_{2}$ is mediated by divacancies at all lithium concentrations Furthermore, due to a strong concentration dependence of the activation barrier, the predicted diffusion coefficient varies by several orders of magnitude with lithium concentration x

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First-principles theory of ionic diffusion with nondilute carriers

The results of a first principles investigation of lithium diffusion within the layered form of are presented. Kinetic Monte Carlo simulations predict that lithium diffusion is mediated through a divacancy mechanism between and and with isolated vacancies at infinite vacancy dilution. The activation barrier for the divacancy migration mechanism depends strongly on lithium concentration resulting in a diffusion coefficient that varies within several orders of magnitude. We also argue that the thermodynamic factor in the expression of the chemical diffusion coefficient plays an important role at high lithium concentration. ©2000 The Electrochemical Society

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Lithium Diffusion in Layered Li x CoO2

/pdf/layered-to-spinel-phase-transition-in-li-x-mno2-b09e7iumiw.pdf

A. Van der Ven

Papers

Li conductivity in lix mpo 4 ( m = mn , fe , co , ni ) olivine materials

First-principles investigation of phase stability in Li x CoO 2

First-principles theory of ionic diffusion with nondilute carriers

Lithium Diffusion in Layered Li x CoO2

Layered-to-Spinel Phase Transition in Li x MnO2