Nec Corporation

Nec Energy Devices, Ltd.

Makiko Uehara

Takehiro Noguchi

Hideaki Sasaki

Daisuke Kawasaki

Kenichi Shimura

Kazuaki Matsumoto

Yuukou Katou

Yoko Hashizume

Shinsaku Saitho

Akinobu Nakamura

Hiroshi Hatakeyama

Hidetoshi Tamura

Ippei Waki

The object is to provide a lithium ion secondary battery which has an excellent cycle property even in high-temperature environment and which has small volume increase. An exemplary embodiment of the invention is a lithium ion secondary battery, comprising: a positive electrode, a negative electrode comprising a negative electrode active material, and an electrolyte liquid; wherein the electrolyte liquid comprises a chain-type fluorinated ester compound represented by a predetermined formula and a chain-type fluorinated ether compound represented by a predetermined formula; wherein the negative electrode active material comprises metal (a) that can be alloyed with lithium, metal oxide (b) that can absorb and desorb lithium ion, and carbon material (c) that can absorb and desorb lithium ion; and wherein metal (a) is silicon, and metal oxide (b) is silicon oxide.

Secondary battery and electrolyte liquid

A lithium secondary battery including a positive electrode including a positive electrode active material capable of intercalating and deintercalating lithium ions, a negative electrode including a negative electrode active material capable of intercalating and deintercalating lithium ions, and a nonaqueous electrolytic solution, wherein the positive electrode active material includes an active material capable of intercalating or deintercalating lithium ions at a potential of 4.5 V or more, and the nonaqueous electrolytic solution includes a particular fluorine-containing ether compound.

Nonaqueous electrolyte with fluorine containing ether compound for lithium secondary battery

It is an object of this exemplary embodiment to provide a lithium ion secondary battery using a positive electrode active material having an operating potential of 4.5 V or more, the lithium ion secondary battery having excellent high temperature cycle characteristics. This exemplary embodiment is a lithium ion secondary battery comprising a positive electrode and a negative electrode capable of intercalating and deintercalating lithium, a separator between the positive electrode and the negative electrode, and an electrolytic solution containing a nonaqueous electrolytic solvent, wherein the positive electrode comprises a positive electrode active material operating at a potential of 4.5 V or more versus lithium, the separator comprises cellulose, a cellulose derivative, or a glass fiber, and the nonaqueous electrolytic solvent comprises a fluorinated solvent.

Lithium ion secondary battery

An active material for a secondary battery whose lifetime characteristics are improved is provided. The active material for a secondary battery includes a first active material represented by Li[M1M2M3]O, wherein M1 is at least one selected from Ni, Cr, Fe, Co, and Cu; M2 is at least one selected from Mn, Ti, and Si, and contains Mn; M3 is at least one selected from Li, B, Mg, Al, Na, and Ca; and 0&#x2266;p, 0&#x3c;m, 0&#x3c;n, and m+n&#x3c;2; and a second active material represented by Li[LiXZMn]O, wherein X is at least one selected from Ni, Cr, Fe, Co, and Cu; Z is at least one selected from Al, Mg, B, Si, Na, Ca, and Ti; and 0&#x2266;q, 0&#x3c;a, 0&#x3c;x, 0&#x2266;z, and a+x+z&#x3c;1.

Active material for secondary battery

A positive electrode active material for a lithium ion secondary battery having high discharge energy and capable of suppressing capacity drop with cycles and a secondary battery using the same are provided at lower cost. A positive electrode active material for a secondary battery according to a first aspect of the exemplary embodiment is represented by the following formula (I): Li(FeNiMn)O(I) where 0.2&#x3c;x&#x2266;1.2, 0&#x3c;y&#x3c;0.5 and 0&#x2266;a&#x2266;1.2. Furthermore, a positive electrode active material for a secondary battery according to a second aspect of the exemplary embodiment is represented by the following formula (II): Li(FeNiMnA)O(II) where 0.2&#x2266;x&#x2266;1.2, 0&#x3c;y&#x3c;0.5, 0&#x2266;a&#x2266;1.2 and 0&#x3c;z&#x2266;0.3; A is at least one selected from the group consisting of Li, B, Na, Mg, Al, K and Ca.

Positive electrode active material for secondary battery and secondary battery using the same

Provided is a lithium ion positive electrode active material for a secondary battery that can realize a high operating voltage and a high capacity while suppressing capacity drop with cycles by using a low-cost material. A positive electrode active material for a secondary battery, which is a lithium manganese composite oxide represented by the following general formula (I)Li(MMnY)(OZ)&#x2003;&#x2003;(I)wherein in the formula (I), 0.5&#x2266;x&#x2266;1.2, 0&#x3c;y&#x2266;0.3, 0&#x2266;a&#x2266;1.2, and 0&#x3c;w&#x2266;1; M contains at least Fe and may further contain at least one selected from the group consisting of Ni, Cr and Cu other than Fe; Y is at least one selected from the group consisting of Li, Be, B, Na, Mg, Al, K, Ca, Ti and Si; and Z is at least one of F and Cl.

The object of an exemplary embodiment of the invention is to provide a secondary battery which contains a positive electrode active material operating at a potential of 4.5 V or higher and which has good cycle property at a high temperature. An exemplary embodiment of the invention is a secondary battery, comprising a positive electrode that can absorb and desorb lithium and an electrolyte liquid; wherein the positive electrode comprises a positive electrode active material that operates at a potential of 4.5 V or higher with respect to lithium; and wherein the electrolyte liquid comprises a fluorinated ether represented by a prescribed formula and a cyclic-type sulfonate represented by a prescribed formula.

Secondary battery

There is provided a novel positive electrode active material for a secondary battery. A positive electrode active material for a secondary battery according to the present exemplary embodiment is represented by the following formula (I):Li(NiCrMnM1)O(I) wherein 0&#x3c;x, 0&#x3c;y, 0&#x3c;z, x+y+z&#x3c;2, and 0&#x2266;a&#x2266;2; and M1 contains at least one selected from the group consisting of Na and Mg. A positive electrode for a secondary battery according to the present exemplary embodiment has the positive electrode active material for a secondary battery according to the present exemplary embodiment. A method for manufacturing a secondary battery according to the present exemplary embodiment includes the steps of applying the positive electrode active material for a secondary battery according to the present exemplary embodiment on a positive electrode current collector to thereby fabricate a positive electrode for a secondary battery; and assembling the secondary battery by using the positive electrode for a secondary battery.

Growing community of inventors

Tokyo, Japan

Makiko Uehara