National Institute of Advanced Industrial Science and Technology

Hiroshi Senoh

Hikari Sakaebe

Masahiro Shikano

Hikaru Sano

Titus Nyamwaro Masese

Tetsuo Sakai

Hiroyuki Kageyama

Mitsuharu Tabuchi

Tomonari Takeuchi

Toshikatsu Kojima

Kuniaki Tatsumi

Hisanori Ando

Nobuhiko Takeichi

An organic sulfur material comprising carbon, hydrogen, oxygen, and sulfur as constituent elements, and having peaks in the vicinity of 482 cm&#x2212;1, 846 cm&#x2212;1, 1066 cm&#x2212;1, 1279 cm&#x2212;1, and 1442 cm&#x2212;1 in a Raman spectrum detected by Raman spectroscopy, the peak in the vicinity of 1442 cm&#x2212;1 being most intense, has a high capacity and high heat resistance, although a liquid organic starting material is used.

Organic sulfur material and method for producing same

By using a potassium ion secondary battery positive electrode active material comprising a potassium compound represented by general formula (1): KMO, wherein M is copper or iron, n is 0.5 to 3.5, and m is 1.5 to 2.5, provided is a potassium ion secondary battery positive electrode active material having higher theoretical discharge capacity and higher effective capacity than a potassium secondary battery using Prussian blue as a positive electrode active material.

Positive electrode active material for potassium ion secondary cell

Provided is a material that can be used as a potassium secondary battery positive electrode active material (particularly a potassium ion secondary battery positive electrode active material), other than Prussian blue, by using a potassium compound and a potassium ion secondary battery positive electrode active material comprising the potassium compound, the potassium compound being represented by general formula (1):KABO,wherein A is a positive divalent element in groups 7 to 11 of the periodic table; B is positive tetravalent silicon, germanium, titanium or manganese, excluding a case in which A is manganese and B is titanium, and a case in which A is cobalt and B is silicon; n is 1.5 to 2.5; and m is 3.5 to 4.5.

Potassium compound and positive electrode active material for potassium ion secondary batteries containing same

The present invention provides a process for producing a lithium sulfide-carbon composite, the process comprising placing a mixture of lithium sulfide and a carbon material having a specific surface area of 60 m/g or more in an electrically-conductive mold in a non-oxidizing atmosphere, and applying a pulsed direct current to the mold while pressurizing the mixture in a non-oxidizing atmosphere, thereby subjecting the lithium sulfide and the carbon material to heating reaction; and a lithium sulfide-carbon composite obtained by this process, the composite having a carbon content of 15 to 70 weight %, and a tap density of 0.4 g/cmor more when the carbon content is 30 weight % or more, or a tap density of 0.5 g/cmor more when the carbon content is less than 30 weight %. The present invention can improve the electronic conductivity of lithium sulfide, which is expected to be put into practical use as a high-capacity positive electrode active material, so as to further enhance the performance of lithium sulfide as a positive electrode active material for lithium ion secondary batteries.

Lithium sulfide-carbon complex, process for producing the complex, and lithium ion secondary battery utilizing the complex

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Osaka, Japan

Hiroshi Senoh