Electrolytes and interphases in Li-ion batteries and beyond.

Energy-storage technologies, including electrical double-layer capacitors and rechargeable batteries, have attracted significant attention for applications in portable electronic devices, electric vehicles, bulk electricity storage at power stations, and “load leveling” of renewable sources, such as solar energy and wind power. Transforming lithium batteries and electric double-layer capacitors requires a step change in the science underpinning these devices, including the discovery of new materials, new electrochemistry, and an increased understanding of the processes on which the devices depend. The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors.

Challenges Facing Lithium Batteries and Electrical Double‐Layer Capacitors

Haegyeom Kim,†,∥ Jihyun Hong,†,∥ Kyu-Young Park,†,∥ Hyungsub Kim,†,∥ Sung-Wook Kim, and Kisuk Kang*,†,‡ †Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 151-742, Republic of Korea ‡Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 151-742, Republic of Korea Nuclear Fuel Cycle Development Group, Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-353, Republic of Korea

Aqueous Rechargeable Li and Na Ion Batteries

Recent progress in high-voltage lithium ion batteries

The layered nickel-rich cathode materials are considered as promising cathode materials for lithium-ion batteries (LIBs) due to their high reversible capacity and low cost. However, several significant challenges, such as the unstable powder properties and limited electrode density, hindered the practical application of the nickel-rich cathode materials with the nickel content over 80%. Herein, important stability issues and in-depth understanding of the nickel-rich cathode materials on the basis of the industrial electrode fabrication condition for the commercialization of the nickel-rich cathode materials are reviewed. A variety of factors threatening the battery safety such as the powder properties, thermal/structural stability are systemically investigated from a material point of view. Furthermore, recent efforts for enhancing the electrochemical stability of the nickel-rich cathode materials are summarized. More importantly, critical key parameters that should be considered for the high energy LIBs at an electrode level are intensively addressed for the first time. Current electrode fabrication condition has a difficulty in increasing the energy density of the battery. Finally, light is shed on the perspectives for the future research direction of the nickel-rich cathode materials with its technical challenges in current state by the practical aspect.

Prospect and Reality of Ni-Rich Cathode for Commercialization

The effect of vinylene carbonate (VC) as electrolyte additive on the formation mechanisms of passivation films covering both electrodes in lithium-ion batteries was investigated by X-ray photoelectron spectroscopy (XPS). LiCo O2 /graphite coin cells using a LiP F6 /ethylene carbonate:diethyl carbonate:dimethyl carbonate liquid electrolyte with or without VC were charged at 20 and 60°C. The identification of VC-derived products formed at the surface of the electrodes was carried out by a dual experimental/theoretical approach. From a classical XPS core peak analysis completed by a detailed interpretation and simulation of valence spectra supported by ab initio calculations, and through direct synthesis of the VC polymer, we could evidence the formation of the radical poly(VC) at the electrode/electrolyte interfaces. We showed that the radical polymerization is the main reaction mechanism of VC contributing to the formation of the passivation layers at the surface of both electrodes. © 2008 The Electrochemical Society.

The Effect of Vinylene Carbonate Additive on Surface Film Formation on Both Electrodes in Li-Ion Batteries

Vinylene carbonate (VC) is a commonly used electrolyte additive in Li-ion batteries because of its beneficial role on the formation of the solid electrolyte interphase. It was shown to contribute to surface film formation on both electrodes of LiCoO 2 /C cells via its radical polymerization mechanism. In this paper, we carried out a comparative study of the role of VC on electrode/electrolyte interfaces in LiCoO 2 /C, LiFePO 4 /C, and L'CoO 2 /Li 4 Ti 5 O 12 systems, in which the potential and the chemical nature of each electrode are changed. Coin-cells were charged at different potentials using a LiPF 6 /ethylene carbonate: diethyl carbonate: dimethyl carbonate liquid electrolyte with or without VC, and the electrodes were analyzed by X-ray photoelectron spectroscopy. We showed there is no interaction between the negative and positive electrodes in the VC polymerization mechanisms, for example, by exchange of chemical species from one electrode to the other, during the first charge. Separate mechanisms occur, although the same VC polymer is deposited at the surface of both electrodes.

C. Siret

Papers

The Effect of Vinylene Carbonate Additive on Surface Film Formation on Both Electrodes in Li-Ion Batteries

Effect of Vinylene Carbonate Additive in Li-Ion Batteries: Comparison of LiCoO2 ∕ C , LiFePO4 ∕ C , and LiCoO2 ∕ Li4Ti5O12 Systems