Gs Yuasa International Ltd.

Toru Tabuchi

Toshiyuki Nukuda

Tokuo Inamasu

Yoshinobu Yasunaga

Yukiko Fujino

Mariko Kohmoto

Katsushi Nishie

Toshiyuki Aoki

Hiroe Nakagawa

Akihiro Fujii

Yuta Kashiwa

Minoru Teshima

Yohei Shibata

Takashi Egawa

Tokuo Inamatsu

The present invention provides a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode having a negative active material, and a non-aqueous electrolyte, characterized in that the negative active material contains composite particle (C), which has silicon-containing particle (A) and electronic conductive additive (B), the silicon-containing particle (A) has a content of carbon, and when measured at a temperature rising rate of 10&#xb1;2&#xb0; C./min by thermogravimetry, said composite particle (C) exhibits two stages of weight loss in the range of 30 to 1000&#xb0; C.

Non-aqueous electrolyte secondary battery

An object is to provide a positive active material for nonaqueous electrolyte secondary battery, which is capable of providing a battery with excellent cycle performance. Provided are a positive active material for nonaqueous electrolyte secondary battery, which includes an Fe-containing lithium vanadium phosphate compound having a NASICON-type structure, wherein in the Fe-containing lithium vanadium phosphate compound, the percentage of iron atoms relative to the sum of vanadium and iron atoms is 2% or more and 20% or less; and the like.

Positive active material for nonaqueous electrolyte secondary batteries and nonaqueous electrolyte secondary battery

The positive active material is a positive active material for a lithium secondary battery, including a lithium transition metal compound that has an olivine crystal structure and contains at least Ni, Fe, and Mn as transition metal elements, wherein when the sum of mole atoms of Ni, Fe, and Mn of transition metal elements contained in the lithium transition metal compound is expressed as 1, and the mole atomic ratios of Ni, Fe, and Mn are represented by a, b, and c (a+b+c=1, a&#x3e;0, b&#x3e;0, c&#x3e;0), respectively, the following is satisfied: 0.85&#x2266;c&#x2266;0.92 and 0.3&#x2266;a/(a+b)&#x2266;0.9.

Positive active material for lithium secondary battery and lithium secondary battery

The present invention provides a LiV(PO)-based positive active material for a lithium secondary battery, which has high discharge capacity and excellent storage performance, particularly high-temperature storage performance; and a lithium secondary battery made using the positive active material. The positive active material for a lithium secondary battery has general formula LiV(PO)(BO)(0&#x3c;x&#x2266;2). It is preferable that x be 2&#x2266;x&#x2266;2. Also provided are a positive electrode for a lithium secondary battery containing the positive active material; and a lithium secondary battery including the positive electrode.

Positive active material for lithium secondary battery, electrode for lithium secondary battery, and lithium secondary battery

It is an object of the present invention to provide a positive electrode material having a large ratio of the discharge capacity around 4 V to the total discharge capacity including the discharge capacity at 4V or lower while making the discharge capacity around 4 V sufficient, for the purpose of providing a lithium secondary battery using a lithium transition metal phosphate compound excellent in thermal stability, utilizing the discharge potential around 4V (vs. Li/Li) that is higher than the discharge potential of LiFePO, and being advantageous with respect to the detection of the end of discharge state, and a lithium secondary battery using the same. The present invention uses a positive active material for a lithium secondary battery containing a lithium transition metal phosphate compound represented by LiMnFeCoPO(0.1&#x2266;x&#x2266;0.2, 0&#x3c;y&#x2266;0.2).

Positive active material for lithium secondary battery, and lithium secondary battery

The invention provides a polyanion-based positive active material which can improve storage stability (especially, high temperature storage stability), charge and discharge cycle performance and the like of a lithium secondary battery, and a lithium secondary battery using the same. The positive active material for a lithium ion secondary battery contains lithium iron cobalt phosphate represented by the general formula: LiFeCoPO(0&#x3c;x&#x2266;0.019, 0&#x2266;y&#x2266;1.2). By using the positive active material for a lithium secondary battery, high temperature storage stability and charge and discharge cycle performance can be improved in comparison with a case where LiFePOcontaining no Co is used. By using the positive active material, a lithium ion secondary battery can be suitable for applications in fields of electric automobiles and industrial batteries in which long lives, high capacities, and high output powers are required.

The present invention provides a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode having a negative active material, and a non-aqueous electrolyte; characterized in that said negative active material contains composite particle (C), which has silicon-containing particle (A) and electronic conductive additive (B), and carbon material (D), wherein the weight of said electronic conductive additive (B) falls within the range of 0.5 wt. % to 60 wt. % to the weight of said composite particle (C). The negative active material contains silicon which is capable of performing high discharge capacity, so that a non-aqueous electrolyte secondary battery having a large discharge capacity can be obtained. In addition, since the negative active material contains the electronic conductive additive (B) and the carbon material (D), the contact conductivity between the silicon-containing particle (A) or between the negative active material improves and, as a result, a non-aqueous electrolyte secondary battery having satisfactory cycle performance can be attained.

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Kyoto, Japan

Toru Tabuchi