A self-cross-linking polymer electrolyte based on polystyrene-incorporated poly͑ethylene oxide͒ ͑PEO͒ containing LiTFSI has been tested in an all solid-state lithium-polymer battery (Li/SP-E/Li x MnO 2 with a solid polymer electrolyte. The polymer electrolyte showed high stability toward metallic lithium. Mechanical properties of the electrolyte film were much improved by incorporating the polystyrene, but ion conductivity was decreased to half of the value obtained in pure PEO electrolyte film. The cell was charged and discharged at a high temperature ͑80°C͒, providing about 80% utilization of the positive electrode. The cell showed good cycle life at 80°C, keeping 90% of the initial capacity after 50 cycles.Lithium-ion technology is rapidly contributing to the state-of-art of secondary systems and has been commercially used in popular portable devices such as cellular phones and note-size computers. However, such batteries are not being rapidly developed for electric vehicles ͑EVs͒ in view of the safety of the devices because the use of a liquid electrolyte may result in problems, i.e., leakage of a flammable electrolyte, production of gases upon overcharge or overdischarge, and a thermal runaway reaction when the battery is heated to high temperatures. On the other hand, an all solid-state lithium/polymer battery ͑LPB͒ using a metallic lithium anode and solvent-free polymer electrolyte has been demonstrated to be the most promising secondary battery for EV applications because of its absence of risk for leakage of liquid electrolyte, its higher energy density, and its shape flexibility. One of the paramount approaches is to use a thin film of polymer electrolyte with high ionic conductivity and strong mechanical integrity. 1-9 High ionic conductivity is expected to improve rate capability. Good mechanical properties are required to protect against shortages, to assure safety reliability, and to make a feasible thin film, thus improving battery-specific energy and rate capability. However, it is difficult to optimize both the energy and rate capability. In the present work, we used a polystyrene-poly͑ethylene oxide͒ ͑PEO͒ block-graft copolymer, which has a microphase-separated structure, a lamellar shape, good ionic conductivity, and excellent mechanical properties, as the polymer electrolyte for a Li/Li x MnO 2 cell. The electrochemical performance, especially the effect of the film thickness on rate capability, was evaluated. ExperimentalThe detailed synthesis condition of the polystyrene-poly͑ethylene oxide͒ block-graft copolymer ͑SE-P͒ is reported elsewhere. 10 The structure of the polymer is shown in Fig. 1. The average molecular weight is 3.4 ϫ 10 5 with an ethylene oxide ͑EO͒ content of 60 wt %. Battery-grade lithium bis͑trifluoromethanesulfonyl͒imide ͑LiTFSI Kishida Chemical Co., Ltd͒ was used as the electrolyte salt and was vacuum dried for 24 h before use. The polymer electrolyte film was prepared by a well-known solvent-casting technique: a known amount of SE-P and LiTFSI, normally an EO/Li ratio of ...

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The addition of ceramics to the polymer electrolyte was found to result in an enhancement of the ionic conductivity, especially at temperatures below the crystalline-amorphous transition (normally at 60°C), as well as the mechanical property, consistent with other previously reported studies. The electrochemical profile of an all solid-state normalLi/LixMnO2 based on the ceramics-modified and ceramics-free poly(ethylene oxide) false(PEOfalse)­LiClO4 electrolyte has also been studied. We found that the addition of some ceramics, e.g., the metal oxides, could suppress the decomposition of PEO toward the cathode thus showing an improved charge/discharge efficiency upon cycling of an all solid-state normalLi/LixMnO2. This improved behavior is most likely linked to the fact that the metal oxide additive can form a stable interaction between the ceramic and the PEO segment, thus stabilizing the PEO structure, and protecting the PEO from oxidation. © 2002 The Electrochemical Society. All rights reserved.

A solvent-free, cross-linked polymer electrolyte based on polyurethane acrylate ͑PUA͒ containing LiTFSI has been prepared and tested in an all-solid-state lithium-polymer battery (Li/PUA/Li 0.33 MnO 2 ). It was found that the new polymer electrolyte could be directly membranous in the absence of any solvent and could be coated directly on a lithium foil or a composite cathode to form an ultrathin membrane of 10-50 m. The PUA electrolyte membrane was thermally stable to 220°C at the Li/Li 0.33 MnO 2 system and had a higher ionic conductivity than a polyethylene oxide based polymer electrolyte below 60°C. The cell exhibited a high initial capacity ͑190 mAh/g͒, a charge-discharge efficiency of above 99%, and could be operated at 40°C.

Diphosphinodithio ligated complexes of nickel(0), nickel(i) and nickel(ii)–alkyl with a reactivity relevant to the C–C bond formation were described.