SODIUM MOLTEN SALT BATTERY

• Main Authors: FUKUNAGA ATSUSHI, ITANI EIKO, NUMATA KOMA, SAKAI SHOICHIRO, INAZAWA SHINJI, NITTA KOJI
• Format: Patent
• Language: English; Japanese
• Published: 08.12.2014
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

PROBLEM TO BE SOLVED: To provide a sodium molten salt battery superior in charge and discharge cycle characteristics.SOLUTION: A sodium molten salt battery comprises: a positive electrode including a positive electrode active material capable of electrochemically occluding and releasing sodium ions; a negative electrode including a negative electrode active material capable of electrochemically occluding and releasing sodium ions; and a molten salt electrolyte including a sodium salt and an ionic liquid in which the sodium salt can dissolve. The negative electrode active material includes a carbon hard to graphitize. The ionic liquid is a salt of a first onium cation which causes no Faraday reaction with the carbon hard to graphitize, and a bis(sulfonyl)imide anion. The molten salt electrolyte includes 1000 ppm or less of a second onium cation by mass ratio. The second onium cation is expressed by the general formula (1): RRRRN, where Rto Rrepresent a hydrogen atom or a methyl group independently of one another. 【課題】充放電サイクル特性に優れたナトリウム溶融塩電池を提供する。【解決手段】電気化学的にナトリウムイオンを吸蔵および放出可能な正極活物質を含む正極と、電気化学的にナトリウムイオンを吸蔵および放出可能な負極活物質を含む負極と、ナトリウム塩およびナトリウム塩を溶解させるイオン性液体を含む溶融塩電解質と、を含み、負極活物質が、難黒鉛化性炭素を含み、イオン性液体が、難黒鉛化性炭素との間でファラデー反応を起こさない第一オニウムカチオンと、ビス（スルフォニル）イミドアニオンとの塩であり、溶融塩電解質が、質量割合で１０００ｐｐｍ以下の第二オニウムカチオンを含み、第二オニウムカチオンは、一般式（１）：Ｒ1Ｒ2Ｒ3Ｒ4Ｎ+で表され、Ｒ1〜Ｒ4は、それぞれ独立に、水素原子またはメチル基である、ナトリウム溶融塩電池。【選択図】図５