Lg Chem, Ltd

Hoechst Aktiengesellschaft

Jürgen Otto Besenhard

Konrad Von Werner

Martin Winter

Gisela Fauler

Joong-Hee Han

Mario Wachtler

Angelika Basch

Kai Christian Möller

Disclosed is a method for producing surface-modified materials, such as core-shell materials with the core and the shell(s) being different distinct phases, or materials with a concentration gradient of one or more dopant or substituent element(s) from the surface to the bulk. The method comprises (i) treating the bulk of material with a solution containing a first solvent and at least one flocculant comprising a soluble polymer so that the flocculant adheres to the bulk; (ii) subsequently contacting the flocculant-treated bulk of step (i) with a dispersion containing a second solvent and the particulate solid particles to deposit the particulate solid particles on the flocculant-treated bulk; and (iii) subsequently treating the resultant of step (ii) with heat. This method can in particular be applied to produce surface-modified cathode materials for Li batteries with improved performance.

Method for the synthesis of surface-modified materials

A secondary battery is comprised of a positive electrode, a negative electrode formed from a lithium storage material, and a non-aqueous electrolyte. The non-aqueous electrolyte includes a lithium salt, non-aqueous aprotic solvent(s), such as ethylen carbonate, propylene carbonate, dimethyl carbonate, ethymethyl carbonate and diethyl carbonate, and a small percentage of at least one organic additive. The negative electrode may comprise a carbon such as graphite, and the positive electrode may comprise a lithiated metal oxide or phosphate, such as LiCoO, LiNiO, LiMnO, LiFePO, or mixtures thereof. The organic additives have one or more unsaturated bonds activated with respect to oxidation by electron-pushing alkyl groups. They are in most cases known to be able to undergo polymerization reactions, such as an anodically induced polymerization especially under certain conditions. The additives are oxidized at the cathode at a potential of more than 4.3 V vs. Li/Li. With these additives in amounts of 0.001 to 10%, a passivation layer is formed on the cathodes, and the sensitiveness of the battery against overcharge is reduced. The electrolyte mixtures do not deteriorate the properties of the battery anodes.

Rechargeable lithium electrochemical cell

The safety of secondary lithium cells is remarkedly enhanced when partially fluorinated ethers of the formulae

Fluorine-containing solvents for lithium batteries having increased

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Graz, Austria

Jürgen Otto Besenhard