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A material for a negative electrode capable of preventing change in the volume of an active material occurring when lithium is doped/dedoped to improve resistance against cycle operations. A material for a negative electrode contains a mixture of a non-carbon material and a carbon material, wherein

A material for a negative electrode capable of preventing change in the volume of an active material occurring when lithium is doped/dedoped to improve resistance against cycle operations. A material for a negative electrode contains a mixture of a non-carbon material and a carbon material, wherein when an assumption is made that the average particle size of the non-carbon material is R.sub.M and the average particle size of the carbon material is R.sub.C, the ratio R.sub.M /R.sub.C is not higher than one, and when an assumption is made that the weight of the non-carbon material is W.sub.M and the weight of the carbon is W.sub.C, the ratio W.sub.M /W.sub.C is not higher than one or a mixture of a silicon compound and a carbon material, wherein when an assumption is made that the average particle size of the silicon compound is R.sub.Si and the average particle size of the carbon material is R.sub.C, the ratio R.sub.Si /R.sub.C is not higher than one.

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[ What is claimed is:] [1.]1. A material for a negative electrode comprising:a mixture of a non-carbon material and a carbon material, wherein an average particle size of the non-carbon material is defined as R.sub.M and an average particle size of the carbon material is defined as R.sub.C such that

[ What is claimed is:] [1.]1. A material for a negative electrode comprising:a mixture of a non-carbon material and a carbon material, wherein an average particle size of the non-carbon material is defined as R.sub.M and an average particle size of the carbon material is defined as R.sub.C such that a ratio R.sub.M /R.sub.C is not higher than one,wherein a weight of the non-carbon material is defined as W.sub.M and a weight of the carbon is defined as W.sub.C such that a ratio W.sub.M /W.sub.C is not higher than one,wherein the non-carbon material constitutes an alloy expressed by a general formula Li.sub.x MM' in association with lithium, where each of M and M' is an element except for Li and C and where a relationship that x.gtoreq.0.01 is satisfied, andwherein at least one of M and M' is an element selected from a group consisting of Si, Sn, Al and In.