Sumitomo Chemical Company, Limited

Tomoari Satoh

Kenji Nakane

Yasunori Nishida

Taketsugu Yamamoto

Kenichiro Kami

Tatsuo Tateno

Kazuyuki Tanino

Takeshi Miyai

Toshihisa Deguchi

Yasuhito Furukawa

Chikashi Akamatsu

Provided is a lithium secondary battery of a high energy density using a cathode active material having an excellent cycle characteristic in charging/discharging at a high capacity and a small irreversible capacity. The lithium secondary battery comprising: a cathode including a material that can be doped/undoped with lithium ions as an active material; an anode including a lithium metal, a lithium alloy, or a material that can be doped/undoped with lithium ions as an active material; and a liquid or solid electrolyte, wherein lithiated nickel dioxide containing tin is used as the cathode active material, and said lithiated nickel dioxide has a peak near 2&thgr;&equals;34.4&deg; and does not have a peak near 2&thgr;&equals;22.5&deg; in the X-ray diffraction pattern by CuK&agr; rays, or the intensity ratio of the peak near 2&thgr;&equals;22.5&deg; to the peak near 2&thgr;&equals;34.4&deg; is 1.2 or less.

Lithium secondary battery and cathode active material for use in lithium secondary battery

The invention provides a cathode for a lithium secondary battery including lithiated nickel dioxide with a large discharge capacity as an active material and having a high density so that a larger amount of the active material can be charged in a battery container with a limited volume, a production method for the same and a lithium secondary battery utilizing the cathode. The cathode for a lithium secondary battery includes lithiated nickel dioxide as an active material, and the lithiated nickel dioxide is produced by firing a mixture of a lithium compound and a nickel compound at a temperature ranging between 350.degree. C. and 800.degree. C. The supernatant obtained by dispersing 5 g of the lithiated nickel dioxide in 100 cm.sup.3 of water in a glass vessel for 5 minutes and allowing the resultant solution to stand for 30 seconds has pH of 12.00 or less. The production method includes the steps of obtaining the lithiated nickel dioxide as above and treating or milling the lithiated nickel dioxide in an atmosphere including carbon dioxide.

Cathode for lithium secondary battery and production method for the same

The invention provides a cathode material for lithium secondary battery containing lithiated nickel dioxide having excellent charge/discharge characteristics and a process for producing the lithiated nickel dioxide, and a lithium secondary battery. That is, the cathode material for lithium secondary battery contains lithiated nickel dioxide having .alpha.-NaFeO.sub.2 structure and shows a coulomb efficiency of 80% or higher at the first charging and discharging, and the process for producing lithiated nickel dioxide comprises dispersing a nickel compound in a lithium nitrate solution, then evaporating the solvent to obtain a mixture of lithium nitrate and the nickel compound and firing the mixture in an atmosphere containing oxygen.

Cathode material for lithium secondary battery and method for producing

The invention provides a cathode material for lithium secondary battery containing lithiated nickel dioxide having excellent charge/discharge characteristics and a process for producing the lithiated nickel dioxide, and a lithium secondary battery. That is, the cathode material for lithium secondary battery contains lithiated nickel dioxide having .alpha.-NaFeO.sub.2 structure and shows a coulomb efficiency of 85% or higher at the first charging and discharging, and the process for producing lithiated nickel dioxide comprises dispersing a nickel compound in a lithium nitrate solution, then evaporating the solvent to obtain a mixture of lithium nitrate and the nickel compound and firing the mixture in an atmosphere containing oxygen.

A lithium secondary battery that includes a cathode containing, as an active material, a material that can be doped/undoped with lithium ions; an anode containing, as an active material, a lithium metal, a lithium alloy or a material that can be doped/undoped with lithium ions; and a liquid or solid electrolyte. In this lithium secondary battery, the active material used in the cathode is lithiated nickel dioxide containing gallium. As a result, the lithium secondary battery attains excellent cycle and overcharge resistance characteristics and has a high energy density.

Lithium secondary battery having a cathode containing galliam

Provided is a lithium secondary battery excellent in initial charge/discharge characteristics and high in capacity comprising lithium-rechargeable cathode and anode and a nonaqueous electrolyte, wherein at least one of the cathode and the anode contains one of the following (A), (B) and (C): (A) a composite material comprising a carbon powder and a binder, which is treated with a silane coupling agent, (B) a composite material comprising a binder and a mixed carbon powder containing 70-99% by weight of a graphite powder and 30-1% by weight of a pseudo-graphitic carbon black, and (C) a composite material comprising a composite oxide powder of lithium and a transition metal, a conductive powder and a binder, which is treated with a silane coupling agent.

Growing community of inventors

Tsukuba, Japan

Tomoari Satoh