Application targets of lithium ion batteries (LIBs) are moving from small-sized mobile devices of information technology to large-scale electric vehicles (xEVs) and energy storage systems (ESSs). Environmental issues and abruptly increasing power demands are pushing high performance energy storage devices or systems onto markets. LIBs are one of the most potential candidates as the energy storage devices mainly due to their high energy densities with fairly good rate capabilities and a fairly long cycle life. As battery systems become larger in terms of stored energy as well as physical size, the safety concerns should be more seriously cared. Each application target has its own specification so that electrode materials should be chosen to meet requirements of the corresponding application. This report diagnoses the current market trends of LIBs as a primary topic, followed by giving an overview of anode and cathode material candidates of LIBs for xEVs and ESSs based on their electrochemical properties.

The Current Move of Lithium Ion Batteries Towards the Next Phase

The ever-increasing demand for high-performing, economical, and safe power storage for portable electronics and electric vehicles stimulates RD in Li-ion cells, the objective of current research is to develop a 5-volt cell, and at the same time to maintain high specific charge capacity, excellent cycling, and safety. Since current anode materials possess working potentials fairly close to the potential of a lithium metal, the focus is on the development of cathode materials. This work reviews and analyzes the current state of the art, achievements, and challenges in the field of high-voltage cathode materials for Li-ion cells. Some suggestions regarding possible approaches for future development in the field are also presented.

Higher, Stronger, Better…︁ A Review of 5 Volt Cathode Materials for Advanced Lithium-Ion Batteries

The high-voltage LiNi0.5Mn1.5O4 (LNMO) spinel is a promising candidate for a positive electrode in lithium ion batteries, but LNMO/graphite full-cells display severe capacity fading issues due to Mn dissolution. In this study, the dissolution behaviors of Mn and Ni were examined systematically under various conditions such as state of charge (SOC), temperature, storage time, and crystal structure of LNMO. In addition, surfaces of calendar- or cycle-aged LNMO and graphite electrodes were analyzed by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), or time-of-flight secondary ion mass spectrometry (TOF-SIMS). The chemical composition of aged electrolyte was determined by gas chromatography (GC) analysis after storage of LNMO electrodes under different conditions. It was found that the amounts of dissolved Mn and Ni and diethyl ether, a decomposition product of diethyl carbonate (DEC) in electrolyte, increased with SOC, temperature, and storage time. The decomposition of electr...

Understanding Transition-Metal Dissolution Behavior in LiNi0.5Mn1.5O4 High-Voltage Spinel for Lithium Ion Batteries

Fracture of Li y Mn 2 O 4 is predicted with a numerical model that calculates the stress generated in spherical particles due to lithium intercalation along the 4-V plateau and phase change along the 3-V plateau. In the former case, fracture is probable at the rates typical of high-power applications, while in the latter case, the probability of fracture is linked not to the discharge rate or particle size, but to the LiMn 2 O 4 /Li 2 Mn 2 O 4 phase ratio. The two-phase material should fracture immediately upon lithium extraction. The effects of variation in thermodynamic factor, diffusion coefficient, and lattice parameter are examined in detail.

A mathematical model of stress generation and fracture in lithium manganese oxide

A revolution in modern electronics has led to the miniaturization and evolution of many portable devices, such as cellular telephones and laptop computers, since the 1980s. This has led to an increasing demand for new and compatible energy storage technologies. Furthermore, a growing awareness of pollution issues has provided a strong impetus for the science and technology community to develop alternatives with ever-higher energy densities, with the ultimate goal of being able to propel electric vehicles. Magnesium's thermodynamic properties make this metal a natural candidate for utilization as an anode in high-energy-density, rechargeable battery systems. We report herein on the results of extensive studies on magnesium anodes and magnesium insertion electrodes in nonaqueous electrolyte solutions. Novel, rechargeable nonaqueous magnesium battery systems were developed based on the research. This work had two major challenges: one was to develop electrolyte solutions with especially high anodic stability in which magnesium anodes can function at a high level of cycling efficiency; the other was to develop a cathode that can reversibly intercalate Mg ions in these electrolyte systems. The new magnesium batteries consist of Mg metal anodes, an electrolyte with a general structure of Mg(AlX(3-n)R(n)R')(2) (R',R = alkyl groups, X = halide) in ethereal solutions (e.g., tetrahydrofuran, polyethers of the "glyme" family), and Chevrel phases of MgMo(3)S(4) stoichiometry as highly reversible cathodes. With their practical energy density expected to be >60 Wh/Kg, the battery systems can be cycled thousands of times with almost no capacity fading. The batteries are an environmentally friendly alternative to lead-acid and nickel-cadmium batteries and are composed of abundant, inexpensive, and nonpoisonous materials. The batteries are expected to provide superior results in large devices that require high-energy density, high cycle life, a high degree of safety, and low-cost components. Further developments in this field are in active progress.

Nonaqueous magnesium electrochemistry and its application in secondary batteries.

Degradation mechanisms in doped spinels of LiM0.05Mn1.95O4 (M=Li, B, Al, Co, and Ni) for Li secondary batteries

Effect of carbon additive on electrochemical performance of LiCoO2 composite cathodes

Cathode properties of two layered manganese dioxides (AxMnO21d?yH2O, where A is the pillaring alkali cations) having different crystal structures were compared in 3 V Li secondary batteries. The materials were prepared from the mixture of KNO 3, LiOH, and MnO at 800 and 10508C, respectively. The 8008C-prepared MnO2 has a trigonal R3m space group with an O3-type oxide-packing pattern, whereas the 10508C material has an orthorhombic Cmcm symmetry with a P2-type oxide-packing pattern. The gallery space where the pillaring cations and water molecules reside is wider in the case of the 800 8C material. Due to the higher mobility of pillaring cations in the 800 8C material and similarity in the oxide-packing pattern (O3-type) to the spinel phases, the pillaring cations are easily leached out during cell cycling, which ultimately leads to a lattice collapse and structural transition t o the spinel-related phases. By contrast, as the 1050 8C material has rather immobile pillaring cations and its oxide-packing pattern (P2type) is far different from that of the spinel phases, this cathode shows better cycling performance, with its structural integri ty being well maintained.

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Factors Controlling the Stability of O3− and P2‐Type Layered MnO2 Structures and Spinel Transition Tendency in Li Secondary Batteries

Crystal Structure and Electrochemical Performance of LiNi 1-x Co x O 2 (x=0.0~1.0) According to Co Substitution

A mixture of saturated and unsaturated light hydrocarbon was used as feed gas for the production of aromatics. Natural gas liquids (NGL) from gas fields and hydrocarbon molecules obtained in the middle of conversion processes could be considered a kind of light hydrocarbon mixture. Therefore, for the conversion of the mixture into aromatics compounds, Zn-impregnated ZSM-5 catalysts were prepared and evaluated by employing different loading of Zn. In addition, the catalytic performance was tested and compared by charging physically mixed two different kinds of catalysts in the bed. The NH3-TPD result showed that the impregnation of Zn led to an increase in the number of medium-strength acid sites, whereas those of weak and strong acid sites were decreased. From the results of the catalytic activity tests, 0.5Zn/ZSM-5 showed the highest aromatics yield. As the amount of Zn loading was further increased to 1 wt.%, the yield of aromatics decreased. The test result in the case of the physically mixed catalysts showed a slightly lower yield in terms of total aromatics, but showed the highest BTX yield. To reveal the relative contribution of each hydrocarbon conversion to aromatics yield, each C2 compound was separately tested for aromatization over Zn/ZSM-5.

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Jin K. Hong

Papers

Degradation mechanisms in doped spinels of LiM0.05Mn1.95O4 (M=Li, B, Al, Co, and Ni) for Li secondary batteries

Effect of carbon additive on electrochemical performance of LiCoO2 composite cathodes

Factors Controlling the Stability of O3− and P2‐Type Layered MnO2 Structures and Spinel Transition Tendency in Li Secondary Batteries

Crystal Structure and Electrochemical Performance of LiNi 1-x Co x O 2 (x=0.0~1.0) According to Co Substitution

Efficient Utilization of Hydrocarbon Mixture to Produce Aromatics over Zn/ZSM-5 and Physically Mixed with ZSM-5