JP4363874B2 - Non-aqueous electrolyte battery - Google Patents

Description

【００４５】
前記アルキルイミダソリウムイオンとしては、例えば、ジアルキルイミダゾリウムイオン、トリアルキルイミダゾリウムイオンなどを挙げることができる。ジアルキルイミダゾリウムイオンとしては、１−メチル−３−エチルイミダゾリウムイオン（ＭＥＩ^＋）が好ましい。一方、トリアルキルイミダゾリウムイオンとしては、１，２−ジエチル−３−プロピルイミダゾリウムイオン（ＤＭＰＩ^＋）が好ましい。
【００４６】
前記四級アンモニムイオンとしては、例えば、テトラアルキルアンモニウムイオン、環状アンモニウムイオンなどを挙げることができる。テトラアルキルアンモニウムイオンとしては、ジメチルエチルメトキシアンモニウムイオン、トリメチルプロピルアンモニウムイオンが好ましい。
【００４７】
常温溶融塩の融点は１００℃以下が好ましく、より好ましい融点は２０℃以下で、さらに好ましい融点は０℃以下である。アルキルイミダゾリウムイオン及び四級アンモニウムイオンのうち少なくとも一方を有機物カチオンとして用いることにより、常温溶融塩の融点を１００℃以下もしくは２０℃以下にすることができると共に、非水電解質と負極との反応性を低くすることができる。
【００４８】
常温溶融塩中のリチウムイオンの濃度は、２０ｍｏｌ％以下であることが好ましい。前記範囲にすることにより、２０℃以下の低温において常温溶融塩が液体の形態を安定に保つことができる。また、常温以下でも常温溶融塩が低粘度を維持することができるため、非水電解質のイオン伝導度を高くすることができる。より好ましい範囲は、１〜１０ｍｏｌ％である。
【００４９】
前記アニオンには、ＢＦ_４ ⁻、ＰＦ_６ ⁻、ＡｓＦ_６ ⁻、ＣｌＯ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻、ＣＦ_３ＣＯＯ⁻、ＣＨ_３ＣＯＯ⁻、ＣＯ_３ ^２−、Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻、Ｎ（Ｃ_２Ｆ_５ＳＯ_２）_２ ⁻及び（ＣＦ_３ＳＯ_２）_３Ｃ⁻よりなる群から選択される少なくとも１種類を使用することが好ましい。複数のアニオンを共存させることにより、融点が２０℃以下もしくは０℃以下の常温溶融塩を容易に形成することができる。より好ましいアニオンとしては、ＢＦ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻、ＣＦ_３ＣＯＯ⁻、ＣＨ_３ＣＯＯ⁻、ＣＯ_３ ^２−、Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻、Ｎ（Ｃ_２Ｆ_５ＳＯ_２）_２ ⁻、（ＣＦ_３ＳＯ_２）_３Ｃ⁻が挙げられる。
【００５０】
５）セパレータ
セパレータとしては、例えば、合成樹脂製不織布、ポリエチレン多孔質フィルム、ポリプロピレン多孔質フィルムなどを用いることができる。
【００５１】
６）容器
容器としては、金属製容器、ラミネートフィルム製容器を用いることができる。
【００５２】
金属製容器としては、例えば、角形あるいは円筒形の金属缶を用いることができる。また、金属製容器の形成材料としては、例えば、アルミニウム、アルミニウム合金、鉄、ステンレスなどを挙げることができる。金属製容器の肉厚は、０．５ｍｍ以下にすることが好ましく、より好ましい範囲は０．２ｍｍ以下である。
【００５３】
ラミネートフィルムとしては、例えば、金属箔と樹脂フィルムとを含む積層フィルムが挙げられる。樹脂フィルムは、例えば、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、ナイロン、ポリエチレンテレフタレート（ＰＥＴ）などの高分子から形成することができる。ラミネートフィルムの厚さは、０．２ｍｍ以下にすることが望ましい。
【００５４】
以上説明した本発明に係る非水電解質電池は、正極活物質を含む正極と、負極活物質を含む負極と、リチウムイオンを含有した常温溶融塩を含む非水電解質とを具備した非水電解質電池であって、
前記正極及び前記負極のうち少なくとも一方の電極は、Ａｌ₂Ｏ₃ 粒子、ＺｒＯ₂ 粒子及びＳｉＯ₂ 粒子よりなる群から選択される少なくとも１種類からなる平均一次粒子径が１〜１００ｎｍの範囲内である金属酸化物粒子を含むことを特徴とするものである。
【００５５】
このような構成にすると、正極及び負極のうち少なくとも一方の電極において、常温溶融塩に対する親和性の高い金属酸化物粒子を活物質粒子表面に均一に分散させることができるため、非水電解質に対する濡れ性を向上することができる。その結果、正極及び負極のうち少なくとも一方の電極において、非水電解質の保持量を増加させることができ、活物質利用率を向上することができるため、非水電解質の大電流性能と低温性能を向上させることができる。その結果、常温溶融塩を含む非水電解質を備え、安全性が高く、かつ大電流性能と低温性能に優れる非水電解質電池を実現することができる。
【００５６】
特に、正極及び負極双方に前述した金属酸化物粒子を含有させることによって、正極及び負極両方の活物質利用率を向上させることができるため、不均一反応が生じるのを抑えることができ、非水電解質電池の大電流性能と低温性能をさらに向上することができる。
【００５７】
また、金属酸化物粒子が含有された電極において、活物質粒子の平均粒径Ｄ（ｎｍ）に対する平均一次粒子径ｄ（ｎｍ）の粒径比（ｄ／Ｄ）を１×１０^-5〜１×１０^-1の範囲内にすることによって、金属酸化物粒子の分散性と金属酸化物粒子の常温溶融塩に対する親和性をさらに向上することができるため、非水電解質電池の大電流性能と低温性能をより向上することができる。
【００５８】
次いで、本発明とは別の非水電解質電池について説明する。
【００５９】
この非水電解質電池は、容器と、前記容器内に収納される正極と、前記容器内に収納される負極と、前記容器内に収容され、リチウムイオンとＢ［（ＯＣＯ）₂］₂ ^-で表されるアニオンとを含有する常温溶融塩を含む非水電解質とを具備する。
【００６０】
また、この非水電解質電池では、正極と負極の間にセパレータを介在させることができる。このセパレータとしては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００６１】
以下、正極、負極及び非水電解質について説明する。なお、容器には、前述した第１の実施形態で説明したのと同様なものを使用することができる。
【００６２】
Ａ）正極
正極活物質としては、例えば、種々の酸化物、硫化物、ポリアニリンやポリピロールなどの導電性ポリマー材料、ジスルフィド系ポリマー材料、イオウ（Ｓ）のような無機材料、フッ化カーボンのような有機材料などが挙げられる。正極活物質には、１種類の材料を単独で用いても、２種類以上の材料を混合して用いても良い。
【００６３】
酸化物及び硫化物の具体例としては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００６４】
好ましい二次電池用正極活物質及び好ましい一次電池用正極活物質には、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００６５】
正極は、例えば、正極活物質と導電剤と結着剤とを適当な溶媒に懸濁させ、得られた懸濁物をアルミニウム箔などの集電体に塗布し、乾燥後、プレスすることにより作製される。
【００６６】
前記導電剤及び前記結着剤としては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００６７】
正極活物質、導電剤及び結着剤の配合比は、正極活物質を８０〜９５重量％、導電剤を３〜２０重量％、結着剤を２〜７重量％の範囲にすることが好ましい。
【００６８】
この正極に、Ａｌ₂Ｏ₃ 粒子、ＺｒＯ₂ 粒子及びＳｉＯ₂ 粒子よりなる群から選択される少なくとも１種類からなる平均一次粒子径が１〜１００ｎｍの範囲内の金属酸化物粒子を含有させても良い。これにより、高温貯蔵特性、大電流特性および低温特性に優れる非水電解質電池を実現することができる。
【００６９】
Ｂ）負極
負極活物質には、リチウムを吸蔵放出する材料を用いるのが好ましく、例えば、リチウム金属、リチウム合金、炭素質物、金属化合物などを挙げることができる。負極には、１種類の負極活物質を用いても、２種類以上の負極活物質を混合して用いても良い。
【００７０】
リチウム合金、リチウムを吸蔵放出する炭素質物および金属化合物としては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００７１】
負極活物質としてリチウムもしくはリチウム合金を用いる場合、リチウム箔やリチウム合金箔をそのまま電極として用いることができる。また、負極活物質としてリチウム合金、炭素質物もしくは金属化合物を用いる場合、粉末状の活物質を用いることができる。
【００７２】
粉末状の活物質を含む負極は、例えば、負極活物質粉末と結着剤とを適当な溶媒に懸濁させ、得られた懸濁物を銅箔などの金属集電体に塗布し、乾燥後、プレスすることにより作製される。前記結着剤としては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。また、この負極には、例えばアセチレンブラック、カーボンブラック、黒鉛、金属粉末などの導電剤をさらに含有させても良い。
【００７３】
負極活物質、導電剤及び結着剤の配合比は、負極活物質を８０〜９８重量％、導電剤を２０重量％以下（０重量％を含む）、結着剤を２〜７重量％の範囲にすることが好ましい。
【００７４】
この負極に、Ａｌ₂Ｏ₃ 粒子、ＺｒＯ₂ 粒子及びＳｉＯ₂ 粒子よりなる群から選択される少なくとも１種類からなる平均一次粒子径が１〜１００ｎｍの範囲内の金属酸化物粒子を含有させても良い。これにより、高温貯蔵特性、大電流特性および低温特性に優れる非水電解質電池を実現することができる。
【００７５】
Ｃ）非水電解質
非水電解質は、リチウムイオンとＢ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンとを含有した常温溶融塩から実質的に形成される液状非水電解質であることが望ましい。Ｂ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンの構造式を下記化３に示す。
【００７６】
【化３】

【００７７】
ここでいう常温溶融塩とは、非水電解質電池の作動温度範囲内（−４０℃〜１００℃）において少なくとも一部が液状である塩を意味する。中でも、室温付近（好ましくは−２０℃〜６０℃）において少なくとも一部が液状である塩を用いるのが好ましい。
【００７８】
常温溶融塩の融点は１００℃以下が好ましく、より好ましい融点は２０℃以下で、さらに好ましい融点は０℃以下である。
【００７９】
常温溶融塩は、さらに有機物カチオンを含有することが好ましい。この有機物カチオンとしては、前述した第１の実施形態で説明したのと同様なものを挙げることができる。
【００８０】
常温溶融塩のＢ［（ＯＣＯ）_２］_２ ⁻の濃度は、５０ｍｏｌ％以下であることが好ましい。これは、Ｂ［（ＯＣＯ）_２］_２ ⁻の濃度が５０ｍｏｌ％を超えると、常温溶融塩の融点上昇あるいは非水電解質のイオン伝導度低下を招く恐れがあるからである。より好ましい濃度範囲は、５〜２５ｍｏｌ％である。この範囲内にすることにより、２０℃以下の低温において常温溶融塩が液体の状態を安定に保つことができる。また、常温以下の雰囲気において常温溶融塩が低粘度を維持することができるため、非水電解質のイオン伝導度を高くすることができる。
【００８１】
常温溶融塩には、Ｂ［（ＯＣＯ）_２］_２ ⁻で表されるアニオン以外のアニオン（以下、第２のアニオンと称す）を含有させることができる。第２のアニオンとしては、例えば、ＢＦ_４ ⁻、ＰＦ_６ ⁻、ＡｓＦ_６ ⁻、ＣｌＯ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻、ＣＦ_３ＣＯＯ⁻、ＣＨ_３ＣＯＯ⁻、ＣＯ_３ ^２−、Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻、Ｎ（Ｃ_２Ｆ_５ＳＯ_２）_２ ⁻及び（ＣＦ_３ＳＯ_２）_３Ｃ⁻よりなる群から選択される少なくとも一種類のアニオンが好ましい。この第２のアニオンを常温溶融塩に含有させることによって、常温溶融塩の融点を低くすることができるため、融点が２０℃以下もしくは０℃以下の常温溶融塩を容易に得ることができる。また、第２のアニオンは、Ｂ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンに比較してイオン半径が小さいため、非水電解質のイオン伝導度を高くすることができる。第２のアニオンのうちより好ましいアニオンとしては、ＢＦ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻、ＣＦ_３ＣＯＯ⁻、ＣＨ_３ＣＯＯ⁻、ＣＯ_３ ^２−、Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻、Ｎ（Ｃ_２Ｆ_５ＳＯ_２）_２ ⁻、（ＣＦ_３ＳＯ_２）_３Ｃ⁻が挙げられる。
【００８２】
常温溶融塩のアニオン成分としてＢ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンのみを使用しても良いが、第２のアニオンを併用する場合には、アニオン成分中の第２のアニオンの割合を８０ｍｏｌ％以下にすることが望ましい。
【００８３】
以上に説明したように、本発明とは別の非水電解質電池は、正極と、負極と、リチウムイオンとＢ［（ＯＣＯ）₂］₂ ^-で表されるアニオンとを含有する常温溶融塩を含む非水電解質とを具備するものである。この電池によれば、高温貯蔵時の放電容量の低下を抑えることができる。
【００８４】
すなわち、リチウム金属、リチウム合金、炭素材料、金属化合物などの各種負極材料は、非水電解質の常温溶融塩に含まれる有機カチオンを電気化学的に還元分解しやすく、このことが常温溶融塩を備えた非水電解質電池の実用化の妨げの一因になっている。
【００８５】
本発明者らは鋭意研究を重ねた結果、リチウムイオンと、Ｂ［（ＯＣＯ）₂］₂ ^-で表されるアニオンと、有機物カチオンとを含有する常温溶融塩が電池作動温度範囲内で液状を保つことができ、この常温溶融塩を含む非水電解質を一次電池あるいは二次電池に用いると、負極による非水電解質の還元分解を抑制することができ、高温貯蔵時の容量低下を抑制できることを見出した。さらに、二次電池の場合には、充放電サイクル寿命を向上できることもわかった。これらは、Ｂ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンが負極上で一部還元分解され、負極表面に、非水電解質の還元分解を抑制するリチウム透過性の良質な皮膜が形成されるためであると考えられる。
【００８６】
また、Ｂ［（ＯＣＯ）_２］_２ ⁻で表されるアニオンには、フッ素原子が含まれていないため、非水電解質の熱安定性を高くして非水電解質電池の安全性を向上することができるばかりか、環境負荷の少ないリチウム乾電池の実現が可能になる。
【００８７】
正極及び負極のうち少なくとも一方の電極に、Ａｌ₂Ｏ₃ 粒子、ＺｒＯ₂ 粒子及びＳｉＯ₂ 粒子よりなる群から選択される少なくとも１種類からなる平均一次粒子径が１〜１００ｎｍの範囲内である金属酸化物粒子を含有させることによって、電極の活物質利用率を向上することができるため、高温貯蔵特性、大電流特性及び低温放電特性に優れる非水電解質電池を実現することができる。
【００８８】
【実施例】
以下、本発明の実施例を図面を参照して詳細に説明する。
【００８９】
（実施例１）
＜正極の作製＞
正極活物質に平均粒径Ｄ₁が３μｍ（３０００ｎｍ）のリチウムコバルト酸化物（ＬｉＣｏＯ_２）粒子を用い、これに平均一次粒子径ｄが２０ｎｍのＡｌ_２Ｏ_３粒子を正極全体に対して１重量％と、導電材として正極全体に対して８重量％の黒鉛粉末と、結着剤として正極全体に対して５重量％のＰＶｄＦとをそれぞれ配合してｎ−メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調製した。得られたスラリーを厚さ１５μｍのアルミニウム箔に塗布し、乾燥し、プレス工程を経て電極密度３．３ｇ／ｃｍ^３の正極を得た。
【００９０】
＜負極の作製＞
平均粒径Ｄ₂が１μｍ（１０００ｎｍ）のチタン酸リチウム（Ｌｉ_４Ｔｉ_５Ｏ_１２）粒子と、平均一次粒子径ｄが２０ｎｍのＡｌ_２Ｏ_３粒子と、導電材としてアセチレンブラックと、結着剤としてＰＶｄＦとを重量比（Ｌｉ_４Ｔｉ_５Ｏ_１２：Ａｌ_２Ｏ_３粒子：導電材：結着剤）で８８：１：５：６となるように配合してｎ−メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調製した。得られたスラリーを厚さ１５μｍのアルミニウム箔に塗布し、乾燥し、プレス工程を経て電極密度２ｇ／ｃｍ^３の負極を得た。
【００９１】
なお、正極活物質粒子、負極活物質粒子および金属酸化物粒子の測定は、下記に説明する方法で行った。
【００９２】
レーザー回折式粒度分布測定装置（島津SALD-300）を用い、まず、ビーカーに試料を約０．１ｇと界面活性剤と１〜２ｍＬの蒸留水を添加して十分に攪拌した後、攪拌水槽に注入し、２秒間隔で６４回光強度分布を測定し、粒度分布データを解析するという方法にて測定した。
【００９３】
また、正極活物質粒子の平均粒径Ｄ₁（ｎｍ）に対する平均一次粒子径ｄ（ｎｍ）の粒径比（ｄ／Ｄ₁）と、負極活物質粒子の平均粒径Ｄ₂（ｎｍ）に対する平均一次粒子径ｄ（ｎｍ）の粒径比（ｄ／Ｄ₂）を下記表１に示す。
【００９４】
＜非水電解質の調製＞
１−メチル−３−エチルイミダゾリウムイオン（ＭＥＩ^＋）と、Ｌｉ^＋と、ＣＦ_３ＳＯ_３ ⁻と、ＢＦ_４ ⁻とをモル比がＭＥＩ^＋：Ｌｉ^＋：ＣＦ_３ＳＯ_３ ⁻：ＢＦ_４ ⁻＝４５：５：２０：３０となるように混合し、２０℃において液状の常温溶融塩を得た。
【００９５】
この常温溶融塩をセパレータのポリエチレン製の多孔質フィルムに含浸させた後、このセパレータで正極表面を被覆した。負極をセパレータを介して正極と対向するように重ね、これらを渦巻状に捲回した後、扁平状にプレス成形することにより扁平型の電極群を得た。肉厚０．１ｍｍのアルミニウム層含有ラミネートフィルムからなる容器内に電極群を収納し、図１示す構造を有し、厚さが３ｍｍで、幅が３５ｍｍで、高さが６２ｍｍの薄型の非水電解質二次電池を作製した。
【００９６】
図1に示すように、扁平型の電極群１は、正極２と負極３をその間にセパレータ４を介在させて扁平形状にした構造を有する。帯状の正極端子５は、正極２に電気的に接続されている。一方、帯状の負極端子６は、負極３に電気的に接続されている。この電極群１は、ラミネートフィルム製容器７内に正極端子５と負極端子６の端部を容器７から延出させた状態で収納されている。なお、ラミネートフィルム製容器７は、ヒートシールにより封止がなされている。
【００９７】
（実施例２〜９）
正極及び負極双方の電極に添加する金属酸化物粒子の種類、平均一次粒子径、配合量、粒径比（ｄ／Ｄ₁）及び粒径比（ｄ／Ｄ₂）を下記表１に示すように設定すること以外は、前述した実施例１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【００９８】
（比較例１）
正極および負極の双方の電極に金属酸化物粒子を添加しないこと以外は、前述した実施例１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【００９９】
（比較例２）
正極及び負極双方の電極に添加する金属酸化物粒子の種類、平均一次粒子径、配合量、粒径比（ｄ／Ｄ₁）及び粒径比（ｄ／Ｄ₂）を下記表１に示すように設定すること以外は、前述した実施例１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１００】
得られた実施例１〜９及び比較例１〜２の非水電解質二次電池について、１００ｍＡの定電流で３Ｖまで充電した後、１．５Ｖまで１００ｍＡの定電流放電を行う充放電サイクルを２０℃で繰り返した。その際の放電初期容量と、１Ａ放電時の容量維持率（１００ｍＡ放電時を１００としたの容量維持率）を下記表１に示す。
【０１０１】
【表１】

【０１０２】
表１から明らかなように、Ａｌ₂Ｏ₃ 粒子、ＺｒＯ₂ 粒子及びＳｉＯ₂ 粒子よりなる群から選択される少なくとも１種類からなる平均一次粒子径が１〜１００ｎｍの金属酸化物粒子を含む正極及び負極を備えた実施例１〜９の二次電池は、金属酸化物無添加の比較例１の二次電池と平均一次粒子径が１００ｎｍを超える比較例２の二次電池に比較して、放電容量が高く、かつ大電流放電特性に優れていることが理解できる。
【０１０３】
（実施例１０）
正極活物質粒子として平均粒径Ｄ₁が５μｍ（５０００ｎｍ）の二酸化マンガン粒子を使用すること以外は、実施例１で説明したのと同様にして薄型の非水電解質一次電池を作製した。
【０１０４】
（比較例３）
正極活物質粒子として平均粒径Ｄ₁が５μｍ（５０００ｎｍ）の二酸化マンガン粒子を使用すること以外は、比較例１で説明したのと同様にして薄型の非水電解質一次電池を作製した。
【０１０５】
実施例１０および比較例３の非水電解質一次電池それぞれについて、二つに分け、一方について５００ｍＡで放電試験を行い、得られた放電容量を下記表2に示す。また、他方について１０００ｍＡで放電試験を行い、得られた放電容量を５００ｍＡでの放電容量を１００％として下記表2に示す。
【０１０６】
【表２】

【０１０７】
表２から明らかなように、実施例１０の一次電池は、大電流放電時に比較例３よりも高容量を得られることがわかる。
【０１０８】
（参考例１１）
＜正極の作製＞
正極活物質にＬｉＦｅＰＯ_４粒子を用い、これに導電材として正極全体に対して８重量％の割合になるように黒鉛粉末と、結着剤として正極全体に対して５重量％となるようにＰＶｄＦとをそれぞれ配合し、これらをｎ−メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調製した。得られたスラリーを厚さが１５μｍのアルミニウム箔に塗布し、乾燥し、プレス工程を経て電極密度３．３ｇ／ｃｍ^３の正極を得た。
【０１０９】
＜負極の作製＞
リチウムアルミニウム合金（合金中のアルミニウム含有量は３原子％）箔を負極として用意した。
【０１１０】
＜非水電解質の調製＞
１−メチル−３−エチルイミダゾリウムイオン（以下、ＭＥＩ^＋と称す）と、Ｌｉ^＋と、Ｂ［（ＯＣＯ）_２］_２ ⁻と、第2のアニオンとしてＢＦ_４ ⁻とをモル比（ＭＥＩ^＋：Ｌｉ^＋：Ｂ［（ＯＣＯ）_２］_２ ⁻：ＢＦ_４ ⁻）が４２：８：８：４２となるように混合し、２０℃において液状である常温溶融塩を得た。
【０１１１】
この常温溶融塩をセパレータのポリエチレン製の多孔質フィルムに含浸させた後、このセパレータで正極表面を被覆した。負極をセパレータを介して正極と対向するように重ね、これらを渦巻状に捲回した後、扁平状にプレス成形することにより扁平型の電極群を得た。肉厚０．１ｍｍのアルミニウム層含有ラミネートフィルムからなる容器内に電極群を収納し、前述した図１示す構造を有し、厚さが３ｍｍで、幅が３５ｍｍで、高さが６２ｍｍの薄型の非水電解質二次電池を作製した。
【０１１２】
（参考例１２〜１３）
第２のアニオンの種類を下記表３に示すように変更すること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１１３】
（参考例１４）
ＭＥＩ^＋と、Ｌｉ^＋と、Ｂ［（ＯＣＯ）_２］_２ ⁻と、第2のアニオンとしてＢＦ_４ ⁻とをモル比（ＭＥＩ^＋：Ｌｉ^＋：Ｂ［（ＯＣＯ）_２］_２ ⁻：ＢＦ_４ ⁻）が４２：８：２０：３０となるように混合し、２０℃において液状である常温溶融塩を得た。
【０１１４】
この常温溶融塩を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１１５】
（参考例１５）
ＭＥＩ^＋と、Ｌｉ^＋と、Ｂ［（ＯＣＯ）_２］_２ ⁻と、第2のアニオンとしてＢＦ_４ ⁻とをモル比（ＭＥＩ^＋：Ｌｉ^＋：Ｂ［（ＯＣＯ）_２］_２ ⁻：ＢＦ_４ ⁻）が４６：４：４：４６となるように混合し、２０℃において液状である常温溶融塩を得た。
【０１１６】
この常温溶融塩を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１１７】
（参考例１６）
負極として厚さ１００μｍのアルミニウム金属箔（純度９９．９９％）を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１１８】
（参考例１７）
チタン酸リチウム（Ｌｉ_４Ｔｉ_５Ｏ_１２）粒子と、導電材としてアセチレンブラックと、結着剤としてＰＶｄＦとを重量比（Ｌｉ_４Ｔｉ_５Ｏ_１２：導電材：結着剤）で８５：１０：５となるように配合し、これらをｎ−メチルピロリドン（ＮＭＰ）溶媒に分散させてスラリーを調製した。得られたスラリーを厚さ１５μｍのアルミニウム箔に塗布し、乾燥し、プレス工程を経て電極密度２ｇ／ｃｍ^３の負極を得た。
【０１１９】
この負極を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１２０】
（参考例１８〜２０）
カチオンの種類を下記表３に示すように変更し、かつカチオンとＬｉ^＋とＢ［（ＯＣＯ）_２］_２ ⁻とＢＦ_４ ⁻とをモル比（カチオン：Ｌｉ^＋：Ｂ［（ＯＣＯ）_２］_２ ⁻：ＢＦ_４ ⁻）が４２：８：２０：３０となるように混合すること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。なお、表３において、ＤＭＰＩ⁺は、１，２−ジエチル−３−プロピルイミダゾリウムイオンを示す。
【０１２１】
（実施例２１）
正極活物質にＬｉＦｅＰＯ_４粒子を用い、これに平均一次粒子径が２０ｎｍのＳｉＯ_２粒子を正極全体に対して１重量％と、これに導電材として正極全体に対して８重量％の割合になるように黒鉛粉末と、結着剤として正極全体に対して５重量％となるようにＰＶｄＦとをそれぞれ配合し、これらをｎ−メチルピロリドン（ＮＭＰ）溶媒に分散してスラリーを調製した。得られたスラリーを厚さが１５μｍのアルミニウム箔に塗布し、乾燥し、プレス工程を経て電極密度３．３ｇ／ｃｍ^３の正極を得た。
【０１２２】
この正極を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１２３】
（比較例４）
ＭＥＩ^＋と、Ｌｉ^＋と、ＢＦ_４ ⁻とをモル比（ＭＥＩ^＋：Ｌｉ^＋：ＢＦ_４ ⁻）が４２：８：５０となるように混合し、２０℃において液状である常温溶融塩を得た。
【０１２４】
この常温溶融塩を非水電解質として用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１２５】
（比較例５）
ＭＥＩ^＋と、Ｌｉ^＋と、Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻とをモル比（ＭＥＩ^＋：Ｌｉ^＋：Ｎ（ＣＦ_３ＳＯ_２）_２ ⁻）が４２：８：５０となるように混合し、２０℃において液状である常温溶融塩を得た。
【０１２６】
この常温溶融塩を非水電解質として用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１２７】
（比較例６）
比較例４で用いたのと同種類の非水電解質と、参考例１７で用いたのと同種類の負極を用いること以外は、前述した参考例１１で説明したのと同様な構成の薄型非水電解質二次電池を組み立てた。
【０１２８】
得られた参考例１１〜２０、実施例２１及び比較例４〜６の非水電解質二次電池について、以下に説明する充放電条件での充放電サイクルを２０℃で行い、放電初期容量と、サイクル寿命（放電容量が初期容量の８０％となったサイクル数）とを測定し、その結果を下記表３に示す。
【０１２９】
＜充放電条件＞
負極としてリチウムアルミニウム合金箔を用いる参考例１１〜１５，１８〜２０および比較例４，５については、１００ｍＡの定電流で４Ｖまで充電した後、３Ｖまで１００ｍＡの定電流放電を行う充放電サイクルを施した。
【０１３０】
負極としてアルミニウム金属箔を用いる参考例１６については、１００ｍＡの定電流で３．８Ｖまで充電した後、１．５Ｖまで１００ｍＡの定電流放電を行う充放電サイクルを施した。
【０１３１】
負極活物質としてチタン酸リチウムを用いる参考例１７及び比較例６については、１００ｍＡの定電流で２．５Ｖまで充電した後、１．５Ｖまで１００ｍＡの定電流放電を行う充放電サイクルを施した。
【０１３２】
また、参考例１１〜２０、実施例２１及び比較例４〜６の非水電解質二次電池について、充電後、８５℃で２０日間貯蔵し、残存容量を測定し（貯蔵前の放電容量を１００％とする）、その結果を下記表３に示す。
【０１３３】
【表３】

【０１３４】
表３から明らかなように、リチウムイオンとＢ［（ＯＣＯ）₂］₂ ^-で表されるアニオンとを含有する常温溶融塩を備えた参考例１１〜２０、実施例２１の二次電池は、Ｂ［（ＯＣＯ）₂］₂ ^-無添加の比較例４〜６に比較して、サイクル寿命が長く、かつ高温貯蔵時の容量残存率が高いことが理解できる。
【０１３５】
（参考例２２）
正極活物質粒子として二酸化マンガン粒子を使用すること以外は、参考例１１で説明したのと同様にして薄型の非水電解質一次電池を作製した。
【０１３６】
（比較例７）
正極活物質粒子として二酸化マンガン粒子を使用すること以外は、比較例４で説明したのと同様にして薄型の非水電解質一次電池を作製した。
【０１３７】
参考例２２および比較例７の非水電解質一次電池それぞれについて、二つに分け、一方については８５℃の高温で１０００時間貯蔵した後、５００ｍＡで放電試験を行った。他方については、高温貯蔵を行うことなく、５００ｍＡで放電試験を行い、得られた電池容量を下記表4に示す。この電池容量を１００％として高温貯蔵後の放電容量を表したものを高温貯蔵時の残存率として下記表4に示す。
【０１３８】
【表４】

【０１３９】
表４から明らかなように、参考例２２の非水電解質一次電池は、比較例７に比べて容量特性と長期間の高温貯蔵特性に優れていることが理解できる。
【０１４０】
なお、本発明は上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合わせにより、種々の発明を形成できる。例えば、実施形態に示される全構成要素から幾つかの構成要素を削除してもよい。さらに、異なる実施形態にわたる構成要素を適宜組み合わせてもよい。
【０１４１】
【発明の効果】
以上詳述したように本発明によれば、常温溶融塩を備えた大電流放電特性に優れる非水電解質電池を提供することができる。
【図面の簡単な説明】
【図１】 実施例１の薄型非水電解質二次電池を示す部分切欠斜視図。
【符号の説明】
１…電極群、２…正極、３…負極、４…セパレータ、５…正極端子、６…負極端子、７…容器。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a primary battery and a secondary battery provided with a nonaqueous electrolyte containing a room temperature molten salt.
[0002]
[Prior art]
At present, lithium primary batteries and lithium ion secondary batteries using an organic electrolyte obtained by dissolving a lithium salt in an organic solvent as a non-aqueous electrolyte are frequently used as a memory backup or driving power source for portable devices. In these batteries, the organic electrolyte is contained in the organic electrolyte, so the vapor pressure tends to be high at high temperatures, and many of the organic solvents are flammable, so consideration must be given to increase safety. .
[0003]
In addition, in electric vehicles (EV), hybrid vehicles (HEV), large power storage batteries, and power tool batteries that require high output, even higher safety and high reliability at high temperatures. Therefore, it is necessary to further improve the safety of the nonaqueous electrolyte. On the other hand, high safety and long life capacitors are similarly required to have high safety electrolytes.
[0004]
Therefore, solid electrolytes made of inorganic solids and room temperature molten salts that are ionic melts that are liquid at room temperature have attracted attention as nonflammable non-aqueous electrolytes. For example, JP-A-4-349365 discloses a lithium battery using a room temperature molten salt.
[0005]
However, a non-aqueous electrolyte containing a room temperature molten salt has a problem in that high high-current performance cannot be obtained because it has a higher viscosity and lower conductivity than a non-aqueous electrolyte made of an organic electrolyte.
[0006]
[Patent Document 1]
JP-A-4-349365 (Claims)
[0007]
[Problems to be solved by the invention]
An object of this invention is to provide the nonaqueous electrolyte battery excellent in the large current performance provided with the nonaqueous electrolyte containing a normal temperature molten salt.
[0009]
[Means for Solving the Problems]
  The present inventionNonThe water electrolyte battery is a non-aqueous electrolyte battery comprising a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte containing a room temperature molten salt containing lithium ions,
  At least one of the positive electrode and the negative electrode is made of Al.₂ O _Three grainChild, ZrO ₂ grainChild and SiO ₂ grainIt contains metal oxide particles having an average primary particle diameter of at least one selected from the group consisting of children in the range of 1 to 100 nm.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
First, a first embodiment of a nonaqueous electrolyte battery according to the present invention will be described.
[0012]
  The nonaqueous electrolyte battery according to the first embodiment includes a container, a positive electrode containing a positive electrode active material, housed in the container, a negative electrode housed in the container and containing a negative electrode active material, and housed in the container. And a non-aqueous electrolyte containing a room temperature molten salt containing lithium ions. Further, at least one of the positive electrode and the negative electrode is made of Al.₂O_Three particle, ZrO₂ particleAnd SiO₂ particleMetal oxide particles having an average primary particle diameter of at least one selected from the group consisting of 1 to 100 nm.
[0013]
Furthermore, in the nonaqueous electrolyte battery of the first embodiment, a separator can be interposed between the positive electrode and the negative electrode.
[0014]
Hereinafter, the metal oxide particles, the positive electrode, the negative electrode, the nonaqueous electrolyte, the separator, and the container will be described.
[0015]
  1) Metal oxide particles
  Metal oxide particles are Al₂O_Three particle, ZrO₂ particleAnd SiO₂ particleIt consists of at least 1 type selected from the group which consists of.
[0016]
The metal oxide particles are included in at least one of the positive electrode and the negative electrode, and the average primary particle diameter of the metal oxide particles may be in the range of 1 to 100 nm for the reason described below. desirable. If the average primary particle diameter exceeds 100 nm, the active material particles will not be uniformly dispersed on the surface, so that the wettability of the active material particles to room temperature molten salt may be reduced, and high current performance may not be obtained. The smaller the average primary particle diameter, the easier it is to uniformly disperse on the surface of the active material particles. However, when the average primary particle diameter is less than 1 nm, the affinity of the metal oxide particles to the room temperature molten salt decreases. There is a possibility that the wettability to room temperature molten salt may not be improved. A more preferable range of the average primary particle diameter is 1 to 50 nm, and a more preferable range is 1 to 20 nm.
[0017]
  Al₂O_Three particle, ZrO₂ particleAnd SiO₂ particleIt is preferable that a functional group having a polarity such as hexamethyldisilazane is bonded to the surface of the electrode since the wettability of the electrode to the room temperature molten salt is further increased.
[0018]
2) Positive electrode
Examples of the positive electrode active material include various oxides, sulfides, conductive polymer materials such as polyaniline and polypyrrole, disulfide polymer materials, inorganic materials such as sulfur (S), and organic materials such as carbon fluoride. Is mentioned. As the positive electrode active material, one type of material may be used alone, or two or more types of materials may be mixed and used.
[0019]
Specific examples of the oxide include manganese dioxide (MnO₂), Iron oxide, copper oxide, nickel oxide, lithium manganese composite oxide (for example, Li_xMn₂O₄, Li_xMnO₂), Lithium nickel composite oxide (for example, Li_xNiO₂), Lithium cobalt composite oxide (for example, Li_xCoO₂), Lithium nickel cobalt composite oxide (for example, LiNi_1-yCo_yO₂), Lithium manganese cobalt composite oxide (for example, LiMn)_yCo_1-yO₂), Spinel type lithium manganese nickel composite oxide (for example, Li_xMn_2-yNi_yO₄), Lithium phosphorus oxide having an olivine structure (for example, Li_xFePO₄, Li_xFe_1-yMn_yPO₄, Li_xCoPO₄Etc.), vanadium oxide (for example, V₂O₅) And the like. On the other hand, as a specific example of sulfide, iron sulfate (for example, Fe₂(SO₄)₃) And the like.
[0020]
Preferred as the positive electrode active material of the secondary battery is a lithium manganese composite oxide (for example, Li_xMn₂O₄), Lithium nickel composite oxide (for example, Li_xNiO₂), Lithium cobalt composite oxide (for example, Li_xCoO₂), Lithium nickel cobalt composite oxide (for example, Li_xNi_1-yCo_yO₂), Spinel type lithium manganese nickel composite oxide (for example, Li_xMn_2-yNi_yO₄), Lithium manganese cobalt composite oxide (for example, Li_xMn_yCo_1-yO₂), Lithium iron phosphate (eg Li_xFePO₄) Etc. X and y are preferably 1 or less (including 0).
[0021]
On the other hand, manganese dioxide, iron oxide, copper oxide, iron sulfide, carbon fluoride and the like are preferable as the positive electrode active material of the primary battery.
[0022]
The average particle diameter of the positive electrode active material particles is preferably in the range of 1 to 100 μm, and more preferably in the range of 2 to 30 μm.
[0023]
When the above-described metal oxide particles are added to the positive electrode, the average particle diameter D of the positive electrode active material particles₁The particle diameter ratio (d / D) of the average primary particle diameter d (nm) of the metal oxide particles to (nm)₁) Is 1 × 10^-Five~ 1x10^-1It is desirable to be within the range. This is due to the reason explained below. Particle size ratio (d / D₁) 1 × 10^-FiveIf it is less than the range, the dispersibility of the metal oxide particles on the surface of the positive electrode active material particles or the affinity of the metal oxide particles for the room temperature molten salt may be lowered. On the other hand, the particle size ratio (d / D₁) Is 1 × 10^-1In the case of exceeding the positive electrode active material particles, the surface of the metal oxide particles rather than the positive electrode active material particles may get wet with the non-aqueous electrolyte and the active material utilization rate of the positive electrode may be reduced. Particle size ratio (d / D₁) Is more preferably 1 × 10^-Four~ 1x10^-2It is.
[0024]
When the metal oxide particles described above are added to the positive electrode, the content of the metal oxide particles in the positive electrode is desirably 10% by weight or less, and a more preferable range is 0.1 to 5% by weight. This is because if the content is large, the battery capacity may decrease, whereas if the content is small, the large current performance and the low-temperature discharge performance may be significantly decreased.
[0025]
In the positive electrode, for example, in addition to the positive electrode active material, the conductive agent, and the binder, the metal oxide particles are suspended in an appropriate solvent as required, and the resulting suspension is collected into a current collector such as an aluminum foil. It is produced by applying to the body, drying, and pressing.
[0026]
Examples of the conductive agent include acetylene black, carbon black, and graphite.
[0027]
Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber.
[0028]
The compounding ratio of the positive electrode active material, the metal oxide particles, the conductive agent and the binder is 80 to 95% by weight of the positive electrode active material, 10% by weight or less (including 0% by weight) of the metal oxide particles, and the conductive agent. It is preferable that the content is 3 to 20% by weight and the binder is in the range of 2 to 7% by weight.
[0029]
3) Negative electrode
As the negative electrode active material, a material that occludes and releases lithium is preferably used, and examples thereof include lithium metal, lithium alloy, carbonaceous material, and metal compound. As the negative electrode, one type of negative electrode active material may be used, or two or more types of negative electrode active materials may be mixed and used.
[0030]
Examples of the lithium alloy include a lithium aluminum alloy, a lithium zinc alloy, a lithium magnesium alloy, a lithium silicon alloy, and a lithium lead alloy.
[0031]
Examples of the carbonaceous material that absorbs and releases lithium include natural graphite, artificial graphite, coke, vapor grown carbon fiber, mesophase pitch carbon fiber, spherical carbon, and resin-fired carbon. Among these, vapor growth carbon fiber, mesophase pitch carbon fiber, and spherical carbon are preferable. In addition, the carbonaceous material has a (002) plane spacing d by X-ray diffraction.₀₀₂Is preferably 0.34 nm or less.
[0032]
Examples of the metal compound include metal oxides, metal sulfides, and metal nitrides. Specific examples of metal oxides include lithium titanate (Li_{4 + x}Ti₅O₁₂), Tungsten oxide (WO₃), Amorphous tin oxide (eg SnB)_0.4P_0.6O_3.1), Tin silicon oxide (SnSiO₃), Silicon oxide (SiO), and the like. As a specific example of metal sulfide, lithium sulfide (TiS₂), Molybdenum sulfide (MoS)₂), Iron sulfide (eg FeS, FeS)₂, Li_xFeS₂) And the like. As a specific example of the metal nitride, lithium cobalt nitride (for example, Li_xCo_yN, 0 <x <4, 0 <y <0.5) and the like.
[0033]
When lithium or lithium alloy is used as the negative electrode active material, lithium foil or lithium alloy foil can be used as an electrode as it is. When lithium foil or lithium alloy foil is used as the negative electrode, the metal oxide particles are contained only in the positive electrode.
[0034]
Moreover, when using a lithium alloy, a carbonaceous material, or a metal compound as a negative electrode active material, the thing of a granular form can be used as a negative electrode active material. In this case, it is desirable to add metal oxide particles to the negative electrode.
[0035]
The average particle size of the negative electrode active material particles is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 1 to 50 μm.
[0036]
When the metal oxide particles described above are included in the negative electrode, the average particle diameter D of the negative electrode active material particles₂The particle diameter ratio (d / D) of the average primary particle diameter d (nm) of the metal oxide particles to (nm)₂) Is 1 × 10^-Five~ 1x10^-1It is desirable to be within the range. This is due to the reason explained below. Particle size ratio (d / D₂) 1 × 10^-FiveIf it is less than the range, the dispersibility of the metal oxide particles on the surface of the negative electrode active material particles or the affinity of the metal oxide particles for the room temperature molten salt may be lowered. On the other hand, the particle size ratio (d / D₂) Is 1 × 10^-1In the case of exceeding the negative electrode active material particles, the surface of the metal oxide particles rather than the negative electrode active material particles may be wetted by the non-aqueous electrolyte and the active material utilization rate of the negative electrode may be reduced. Particle size ratio (d / D₂) Is more preferably 1 × 10^-Four~ 1x10^-2It is.
[0037]
When the metal oxide particles described above are contained in the negative electrode, the content of the metal oxide particles in the negative electrode is desirably 10% by weight or less, and a more preferable range is 0.1 to 5% by weight. This is because if the content is large, the battery capacity may decrease, whereas if the content is small, the large current performance and the low-temperature discharge performance may be significantly decreased.
[0038]
In the case of using a negative electrode active material in a granular form, for example, the negative electrode is obtained by suspending metal oxide particles in an appropriate solvent, if necessary, in addition to the negative electrode active material particles and the binder. An object is applied to a metal current collector such as a copper foil, dried, and then pressed. Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine rubber, and styrene butadiene rubber. Further, the negative electrode may further contain a conductive agent such as acetylene black, carbon black, graphite, and metal powder.
[0039]
The compounding ratio of the negative electrode active material, the metal oxide particles, the conductive agent and the binder is 80 to 98% by weight of the negative electrode active material, 10% by weight or less (including 0% by weight) of the metal oxide particles, and the conductive agent. It is preferable to be 20% by weight or less (including 0% by weight) and the binder is in the range of 2 to 7% by weight.
[0040]
4) Non-aqueous electrolyte
The non-aqueous electrolyte is preferably a liquid non-aqueous electrolyte substantially formed from a room temperature molten salt containing lithium ions. A non-aqueous electrolyte battery including such a liquid non-aqueous electrolyte can increase safety.
[0041]
The term “normal temperature molten salt” as used herein means a salt that is at least partially liquid in the operating temperature range (−40 ° C. to 100 ° C.) of the nonaqueous electrolyte battery. Among them, it is preferable to use a salt that is at least partially liquid around room temperature (preferably -20 ° C to 60 ° C).
[0042]
The room temperature molten salt is preferably an ionic melt composed of lithium ions, organic cations, and anions.
[0043]
The organic cation is preferably an organic cation having a skeleton represented by the following chemical formula 2, and among them, alkyl imidazolium ions and quaternary ammonium ions are preferable.
[0044]
[Chemical formula 2]

[0045]
Examples of the alkyl imidazolium ions include dialkyl imidazolium ions and trialkyl imidazolium ions. Dialkylimidazolium ions include 1-methyl-3-ethylimidazolium ion (MEI).⁺) Is preferred. On the other hand, as the trialkylimidazolium ion, 1,2-diethyl-3-propylimidazolium ion (DMPI) is used.⁺) Is preferred.
[0046]
Examples of the quaternary ammonium ions include tetraalkylammonium ions and cyclic ammonium ions. As the tetraalkylammonium ion, dimethylethylmethoxyammonium ion and trimethylpropylammonium ion are preferable.
[0047]
The melting point of the room temperature molten salt is preferably 100 ° C. or lower, more preferably 20 ° C. or lower, and still more preferably 0 ° C. or lower. By using at least one of alkyl imidazolium ions and quaternary ammonium ions as an organic cation, the melting point of the room temperature molten salt can be made 100 ° C. or lower or 20 ° C. or lower, and the reactivity between the nonaqueous electrolyte and the negative electrode Can be lowered.
[0048]
The concentration of lithium ions in the room temperature molten salt is preferably 20 mol% or less. By setting it in the above range, the molten salt at room temperature can be kept in a stable liquid form at a low temperature of 20 ° C. or lower. Further, since the room temperature molten salt can maintain a low viscosity even at room temperature or lower, the ionic conductivity of the nonaqueous electrolyte can be increased. A more preferable range is 1 to 10 mol%.
[0049]
The anion includes BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻, ClO₄ ⁻, CF₃SO₃ ⁻, CF₃COO⁻, CH₃COO⁻, CO₃ ^2-, N (CF₃SO₂)₂ ⁻, N (C₂F₅SO₂)₂ ⁻And (CF₃SO₂)₃C⁻It is preferable to use at least one selected from the group consisting of: By allowing a plurality of anions to coexist, a room temperature molten salt having a melting point of 20 ° C. or lower or 0 ° C. or lower can be easily formed. As a more preferred anion, BF₄ ⁻, CF₃SO₃ ⁻, CF₃COO⁻, CH₃COO⁻, CO₃ ^2-, N (CF₃SO₂)₂ ⁻, N (C₂F₅SO₂)₂ ⁻, (CF₃SO₂)₃C⁻Is mentioned.
[0050]
5) Separator
As a separator, a synthetic resin nonwoven fabric, a polyethylene porous film, a polypropylene porous film, etc. can be used, for example.
[0051]
6) Container
As the container, a metal container or a laminate film container can be used.
[0052]
As the metal container, for example, a rectangular or cylindrical metal can can be used. Examples of the material for forming the metal container include aluminum, aluminum alloy, iron, and stainless steel. The wall thickness of the metal container is preferably 0.5 mm or less, and more preferably 0.2 mm or less.
[0053]
Examples of the laminate film include a laminated film including a metal foil and a resin film. The resin film can be formed of a polymer such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET), for example. The thickness of the laminate film is desirably 0.2 mm or less.
[0054]
  The nonaqueous electrolyte battery according to the present invention described above includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and a nonaqueous electrolyte containing a room temperature molten salt containing lithium ions. Because
  At least one of the positive electrode and the negative electrode is made of Al.₂O_Three particle, ZrO₂ particleAnd SiO₂ particleIt contains metal oxide particles having an average primary particle diameter of at least one selected from the group consisting of 1 to 100 nm.
[0055]
In such a configuration, at least one of the positive electrode and the negative electrode can uniformly disperse the metal oxide particles having a high affinity for the room temperature molten salt on the surface of the active material particles, so that the wetness to the non-aqueous electrolyte is increased. Can be improved. As a result, in at least one of the positive electrode and the negative electrode, the amount of nonaqueous electrolyte retained can be increased, and the active material utilization rate can be improved. Can be improved. As a result, it is possible to realize a nonaqueous electrolyte battery that includes a nonaqueous electrolyte containing a room temperature molten salt, has high safety, and is excellent in large current performance and low temperature performance.
[0056]
In particular, by including the metal oxide particles described above in both the positive electrode and the negative electrode, it is possible to improve the active material utilization rate of both the positive electrode and the negative electrode. The large current performance and low temperature performance of the electrolyte battery can be further improved.
[0057]
In the electrode containing metal oxide particles, the particle size ratio (d / D) of the average primary particle diameter d (nm) to the average particle diameter D (nm) of the active material particles is 1 × 10.^-Five~ 1x10^-1By making it within the range, the dispersibility of the metal oxide particles and the affinity of the metal oxide particles to the room temperature molten salt can be further improved, thereby further improving the high current performance and low temperature performance of the nonaqueous electrolyte battery. can do.
[0058]
  Next, the present inventionDifferent fromNon-aqueous electrolyteIn the pondexplain about.
[0059]
  ThisNonThe water electrolyte battery includes a container, a positive electrode stored in the container, a negative electrode stored in the container, a lithium ion and B [(OCO)₂]₂ ^-And a non-aqueous electrolyte containing a room temperature molten salt containing an anion represented by:
[0060]
  Also,thisIn the nonaqueous electrolyte battery, a separator can be interposed between the positive electrode and the negative electrode. As this separator, the thing similar to what was demonstrated in 1st Embodiment mentioned above can be mentioned.
[0061]
Hereinafter, the positive electrode, the negative electrode, and the nonaqueous electrolyte will be described. In addition, the thing similar to what was demonstrated in 1st Embodiment mentioned above can be used for a container.
[0062]
A) Positive electrode
Examples of the positive electrode active material include various oxides, sulfides, conductive polymer materials such as polyaniline and polypyrrole, disulfide polymer materials, inorganic materials such as sulfur (S), and organic materials such as carbon fluoride. Is mentioned. As the positive electrode active material, one type of material may be used alone, or two or more types of materials may be mixed and used.
[0063]
Specific examples of the oxide and sulfide include the same as those described in the first embodiment.
[0064]
Examples of the preferable positive electrode active material for secondary battery and the preferable positive electrode active material for primary battery include the same materials as those described in the first embodiment.
[0065]
For example, the positive electrode is obtained by suspending a positive electrode active material, a conductive agent, and a binder in a suitable solvent, applying the obtained suspension to a current collector such as an aluminum foil, drying, and then pressing. Produced.
[0066]
Examples of the conductive agent and the binder include the same as those described in the first embodiment.
[0067]
The mixing ratio of the positive electrode active material, the conductive agent and the binder is preferably 80 to 95% by weight of the positive electrode active material, 3 to 20% by weight of the conductive agent, and 2 to 7% by weight of the binder. .
[0068]
  To this positive electrode, Al₂O_Three particle, ZrO₂ particleAnd SiO₂ particleYou may contain the metal oxide particle in the range whose average primary particle diameter which consists of at least 1 type selected from the group which consists of 1-100 nm. Thereby, a nonaqueous electrolyte battery excellent in high temperature storage characteristics, large current characteristics and low temperature characteristics can be realized.
[0069]
B) Negative electrode
As the negative electrode active material, a material that occludes and releases lithium is preferably used, and examples thereof include lithium metal, lithium alloy, carbonaceous material, and metal compound. As the negative electrode, one type of negative electrode active material may be used, or two or more types of negative electrode active materials may be mixed and used.
[0070]
Examples of the lithium alloy, the carbonaceous material that absorbs and releases lithium, and the metal compound include the same materials as those described in the first embodiment.
[0071]
When lithium or lithium alloy is used as the negative electrode active material, lithium foil or lithium alloy foil can be used as an electrode as it is. Moreover, when using a lithium alloy, a carbonaceous material, or a metal compound as a negative electrode active material, a powdery active material can be used.
[0072]
The negative electrode containing a powdered active material is prepared by, for example, suspending the negative electrode active material powder and a binder in an appropriate solvent, and applying the obtained suspension to a metal current collector such as a copper foil and drying Thereafter, it is manufactured by pressing. Examples of the binder include those similar to those described in the first embodiment. Further, the negative electrode may further contain a conductive agent such as acetylene black, carbon black, graphite, and metal powder.
[0073]
The compounding ratio of the negative electrode active material, the conductive agent and the binder is 80 to 98% by weight of the negative electrode active material, 20% by weight or less (including 0% by weight) of the conductive agent, and 2 to 7% by weight of the binder. It is preferable to make the range.
[0074]
  In this negative electrode, Al₂O_Three particle, ZrO₂ particleAnd SiO₂ particleYou may contain the metal oxide particle in the range whose average primary particle diameter which consists of at least 1 type selected from the group which consists of 1-100 nm. Thereby, a nonaqueous electrolyte battery excellent in high temperature storage characteristics, large current characteristics and low temperature characteristics can be realized.
[0075]
C) Non-aqueous electrolyte
Non-aqueous electrolytes are lithium ions and B [(OCO)₂]₂ ⁻It is desirable that the liquid non-aqueous electrolyte is substantially formed from a room temperature molten salt containing an anion represented by: B [(OCO)₂]₂ ⁻The structural formula of the anion represented by the formula is shown in the following chemical formula 3.
[0076]
[Chemical 3]

[0077]
The term “normal temperature molten salt” as used herein means a salt that is at least partially liquid in the operating temperature range (−40 ° C. to 100 ° C.) of the nonaqueous electrolyte battery. Among them, it is preferable to use a salt that is at least partially liquid around room temperature (preferably -20 ° C to 60 ° C).
[0078]
The melting point of the room temperature molten salt is preferably 100 ° C. or lower, more preferably 20 ° C. or lower, and still more preferably 0 ° C. or lower.
[0079]
The room temperature molten salt preferably further contains an organic cation. As this organic cation, the same thing as what was demonstrated in 1st Embodiment mentioned above can be mentioned.
[0080]
B [(OCO) of room temperature molten salt₂]₂ ⁻The concentration of is preferably 50 mol% or less. This is B [(OCO)₂]₂ ⁻This is because if the concentration of exceeds 50 mol%, the melting point of the ambient temperature molten salt may increase or the ionic conductivity of the nonaqueous electrolyte may decrease. A more preferable concentration range is 5 to 25 mol%. By setting it within this range, the molten salt at room temperature can be kept stable at a low temperature of 20 ° C. or lower. Moreover, since the normal temperature molten salt can maintain a low viscosity in an atmosphere at or below normal temperature, the ionic conductivity of the nonaqueous electrolyte can be increased.
[0081]
For room temperature molten salt, B [(OCO)₂]₂ ⁻An anion other than the anion represented by (hereinafter referred to as the second anion) can be contained. As the second anion, for example, BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻, ClO₄ ⁻, CF₃SO₃ ⁻, CF₃COO⁻, CH₃COO⁻, CO₃ ^2-, N (CF₃SO₂)₂ ⁻, N (C₂F₅SO₂)₂ ⁻And (CF₃SO₂)₃C⁻At least one kind of anion selected from the group consisting of By including this second anion in the room temperature molten salt, the melting point of the room temperature molten salt can be lowered, so that a room temperature molten salt having a melting point of 20 ° C. or lower or 0 ° C. or lower can be easily obtained. The second anion is B [(OCO).₂]₂ ⁻Since the ionic radius is smaller than that of the anion represented by the formula (1), the ionic conductivity of the nonaqueous electrolyte can be increased. As a more preferable anion among the second anions, BF₄ ⁻, CF₃SO₃ ⁻, CF₃COO⁻, CH₃COO⁻, CO₃ ^2-, N (CF₃SO₂)₂ ⁻, N (C₂F₅SO₂)₂ ⁻, (CF₃SO₂)₃C⁻Is mentioned.
[0082]
B [(OCO) as an anionic component of room temperature molten salt₂]₂ ⁻However, when the second anion is used in combination, the proportion of the second anion in the anion component is preferably 80 mol% or less.
[0083]
  Less thanaboveAs explained, the present inventionWhat isAnother non-aqueous electrolyte battery includes a positive electrode, a negative electrode, lithium ions and B [(OCO).₂]₂ ^-And a non-aqueous electrolyte containing a room temperature molten salt containing an anion represented by: thisbatteryAccording to this, it is possible to suppress a decrease in discharge capacity during high-temperature storage.
[0084]
That is, various negative electrode materials such as lithium metal, lithium alloy, carbon material, metal compound, etc. are easily subjected to electrochemical reduction and decomposition of organic cations contained in the non-aqueous electrolyte room temperature molten salt, which is provided with the room temperature molten salt. This is one of the factors that hinder the practical application of non-aqueous electrolyte batteries.
[0085]
As a result of intensive studies, the present inventors have found that lithium ions and B [(OCO)₂]₂ ^-When the non-aqueous electrolyte containing this room temperature molten salt is used for a primary battery or a secondary battery, the room temperature molten salt containing an anion represented by the formula (1) and an organic cation can be kept in a liquid state within the battery operating temperature range. It has been found that reductive decomposition of the non-aqueous electrolyte by the negative electrode can be suppressed, and a decrease in capacity during high temperature storage can be suppressed. Furthermore, in the case of the secondary battery, it was also found that the charge / discharge cycle life can be improved. These are B [(OCO)₂]₂ ⁻This is thought to be because a part of the anion represented by the above is reductively decomposed on the negative electrode, and a lithium-permeable high-quality film that suppresses the reductive decomposition of the nonaqueous electrolyte is formed on the negative electrode surface.
[0086]
Also, B [(OCO)₂]₂ ⁻Since the anion represented by the formula does not contain fluorine atoms, it can not only increase the thermal stability of the non-aqueous electrolyte and improve the safety of the non-aqueous electrolyte battery, but also a lithium battery that has a low environmental impact. Can be realized.
[0087]
  Al is applied to at least one of the positive electrode and the negative electrode.₂O_Three particle, ZrO₂ particleAnd SiO₂ particleSince the active material utilization rate of the electrode can be improved by including metal oxide particles having an average primary particle diameter of at least one selected from the group consisting of 1 to 100 nm, a high temperature A nonaqueous electrolyte battery having excellent storage characteristics, large current characteristics, and low temperature discharge characteristics can be realized.
[0088]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0089]
Example 1
<Preparation of positive electrode>
Average particle diameter D in the positive electrode active material₁Is 3 μm (3000 nm) lithium cobalt oxide (LiCoO₂) Al particles having an average primary particle diameter d of 20 nm.₂O₃1% by weight of the particles with respect to the whole positive electrode, 8% by weight of graphite powder with respect to the whole of the positive electrode as a conductive material, and 5% by weight of PVdF with respect to the whole of the positive electrode as a binder, respectively. A slurry was prepared by dispersing in methylpyrrolidone (NMP) solvent. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and subjected to a pressing process to an electrode density of 3.3 g / cm.³The positive electrode was obtained.
[0090]
<Production of negative electrode>
Average particle size D₂Is 1 μm (1000 nm) of lithium titanate (Li₄Ti₅O₁₂) Al particles with an average primary particle diameter d of 20 nm₂O₃The weight ratio of particles, acetylene black as a conductive material, and PVdF as a binder (Li₄Ti₅O₁₂: Al₂O₃Particles: Conductive material: Binder) were blended so as to be 88: 1: 5: 6 and dispersed in an n-methylpyrrolidone (NMP) solvent to prepare a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and subjected to a pressing process to an electrode density of 2 g / cm.³The negative electrode was obtained.
[0091]
In addition, the measurement of a positive electrode active material particle, a negative electrode active material particle, and a metal oxide particle was performed by the method demonstrated below.
[0092]
Using a laser diffraction particle size distribution analyzer (Shimadzu SALD-300), first add about 0.1 g of a sample, a surfactant, and 1 to 2 mL of distilled water to a beaker and stir well. The light intensity distribution was measured 64 times at intervals of 2 seconds, and the particle size distribution data was analyzed.
[0093]
Further, the average particle diameter D of the positive electrode active material particles₁Particle size ratio (d / D) of average primary particle diameter d (nm) to (nm)₁) And the average particle diameter D of the negative electrode active material particles₂Particle size ratio (d / D) of average primary particle diameter d (nm) to (nm)₂) Is shown in Table 1 below.
[0094]
<Preparation of non-aqueous electrolyte>
1-methyl-3-ethylimidazolium ion (MEI⁺) And Li⁺And CF₃SO₃ ⁻And BF₄ ⁻The molar ratio is MEI⁺: Li⁺: CF₃SO₃ ⁻: BF₄ ⁻= 45: 5: 20: 30 was mixed to obtain a liquid room temperature molten salt at 20 ° C.
[0095]
After impregnating the polyethylene porous film of the separator with this room temperature molten salt, the surface of the positive electrode was covered with this separator. The negative electrode was stacked so as to face the positive electrode with a separator interposed therebetween, and these were wound in a spiral shape, and then pressed into a flat shape to obtain a flat electrode group. An electrode group is housed in a container made of an aluminum layer-containing laminate film having a wall thickness of 0.1 mm, and has the structure shown in FIG. An electrolyte secondary battery was produced.
[0096]
As shown in FIG. 1, the flat electrode group 1 has a structure in which a positive electrode 2 and a negative electrode 3 are flattened with a separator 4 interposed therebetween. The strip-like positive electrode terminal 5 is electrically connected to the positive electrode 2. On the other hand, the strip-like negative electrode terminal 6 is electrically connected to the negative electrode 3. The electrode group 1 is housed in a laminate film container 7 with the ends of the positive electrode terminal 5 and the negative electrode terminal 6 extended from the container 7. The laminated film container 7 is sealed by heat sealing.
[0097]
(Examples 2-9)
Type, average primary particle size, blending amount, particle size ratio (d / D) of metal oxide particles added to both positive and negative electrodes₁) And particle size ratio (d / D)₂) Was set as shown in Table 1 below, and a thin nonaqueous electrolyte secondary battery having the same configuration as described in Example 1 was assembled.
[0098]
(Comparative Example 1)
A thin nonaqueous electrolyte secondary battery having the same configuration as described in Example 1 was assembled except that the metal oxide particles were not added to both the positive electrode and the negative electrode.
[0099]
(Comparative Example 2)
Type, average primary particle size, blending amount, particle size ratio (d / D) of metal oxide particles added to both positive and negative electrodes₁) And particle size ratio (d / D)₂) Was set as shown in Table 1 below, and a thin nonaqueous electrolyte secondary battery having the same configuration as described in Example 1 was assembled.
[0100]
About the obtained non-aqueous electrolyte secondary battery of Examples 1-9 and Comparative Examples 1-2, after charging to 3V with a constant current of 100 mA, a charge / discharge cycle for carrying out a constant current discharge of 100 mA to 1.5V Repeated at ° C. Table 1 below shows the initial discharge capacity and the capacity retention ratio during 1 A discharge (capacity retention ratio when 100 mA discharge is 100).
[0101]
[Table 1]

[0102]
  As is clear from Table 1, Al₂O_Three particle, ZrO₂ particleAnd SiO₂ particleThe secondary batteries of Examples 1 to 9 including the positive electrode and the negative electrode including metal oxide particles having an average primary particle diameter of 1 to 100 nm made of at least one selected from the group consisting of: Compared to the secondary battery of Comparative Example 1 and the secondary battery of Comparative Example 2 having an average primary particle diameter exceeding 100 nm, it can be understood that the discharge capacity is high and the large current discharge characteristics are excellent.
[0103]
(Example 10)
Average particle diameter D as positive electrode active material particles₁A thin nonaqueous electrolyte primary battery was produced in the same manner as described in Example 1 except that 5 μm (5000 nm) manganese dioxide particles were used.
[0104]
(Comparative Example 3)
Average particle diameter D as positive electrode active material particles₁A thin non-aqueous electrolyte primary battery was fabricated in the same manner as described in Comparative Example 1 except that manganese dioxide particles having a thickness of 5 μm (5000 nm) were used.
[0105]
Each of the nonaqueous electrolyte primary batteries of Example 10 and Comparative Example 3 was divided into two, one of which was subjected to a discharge test at 500 mA, and the obtained discharge capacity is shown in Table 2 below. The other was subjected to a discharge test at 1000 mA, and the obtained discharge capacity is shown in Table 2 below, assuming that the discharge capacity at 500 mA is 100%.
[0106]
[Table 2]

[0107]
As is clear from Table 2, it can be seen that the primary battery of Example 10 can obtain a higher capacity than Comparative Example 3 during large current discharge.
[0108]
  (referenceExample 11)
  <Preparation of positive electrode>
  LiFePO as positive electrode active material₄Using the particles, graphite powder as a conductive material and a proportion of 8% by weight with respect to the whole positive electrode, and PVdF as a binder to 5% by weight with respect to the whole positive electrode, These were dispersed in n-methylpyrrolidone (NMP) solvent to prepare a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and subjected to a pressing process to an electrode density of 3.3 g / cm.³The positive electrode was obtained.
[0109]
<Production of negative electrode>
A lithium aluminum alloy (aluminum content in the alloy was 3 atomic%) foil was prepared as a negative electrode.
[0110]
<Preparation of non-aqueous electrolyte>
1-methyl-3-ethylimidazolium ion (hereinafter referred to as MEI)⁺Li) and Li⁺And B [(OCO)₂]₂ ⁻And BF as the second anion₄ ⁻And the molar ratio (MEI⁺: Li⁺: B [(OCO)₂]₂ ⁻: BF₄ ⁻) Was 42: 8: 8: 42, and a room temperature molten salt that was liquid at 20 ° C. was obtained.
[0111]
After impregnating the polyethylene porous film of the separator with this room temperature molten salt, the surface of the positive electrode was covered with this separator. The negative electrode was stacked so as to face the positive electrode with a separator interposed therebetween, and these were wound in a spiral shape, and then pressed into a flat shape to obtain a flat electrode group. The electrode group is housed in a container made of an aluminum layer-containing laminate film having a wall thickness of 0.1 mm, and has the structure shown in FIG. 1 described above, and is thin with a thickness of 3 mm, a width of 35 mm, and a height of 62 mm. A non-aqueous electrolyte secondary battery was produced.
[0112]
  (referenceExamples 12-13)
  As described above, except that the type of the second anion is changed as shown in Table 3 below.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0113]
  (referenceExample 14)
  MEI⁺And Li⁺And B [(OCO)₂]₂ ⁻And BF as the second anion₄ ⁻And the molar ratio (MEI⁺: Li⁺: B [(OCO)₂]₂ ⁻: BF₄ ⁻) Was 42: 8: 20: 30, and a room temperature molten salt that was liquid at 20 ° C. was obtained.
[0114]
  Except for using this room temperature molten salt, as described above.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0115]
  (referenceExample 15)
  MEI⁺And Li⁺And B [(OCO)₂]₂ ⁻And BF as the second anion₄ ⁻And the molar ratio (MEI⁺: Li⁺: B [(OCO)₂]₂ ⁻: BF₄ ⁻) Was 46: 4: 4: 46, and a room temperature molten salt that was liquid at 20 ° C. was obtained.
[0116]
  Except for using this room temperature molten salt, as described above.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0117]
  (referenceExample 16)
  As described above, except that an aluminum metal foil (purity 99.99%) having a thickness of 100 μm is used as the negative electrode.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0118]
  (referenceExample 17)
  Lithium titanate (Li₄Ti₅O₁₂) Particles, acetylene black as the conductive material, and PVdF as the binder (Li₄Ti₅O₁₂: Conductive material: binder) so as to be 85: 10: 5, and these were dispersed in an n-methylpyrrolidone (NMP) solvent to prepare a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and subjected to a pressing process to an electrode density of 2 g / cm.³The negative electrode was obtained.
[0119]
  Except for using this negative electrode, it was described above.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0120]
  (referenceExamples 18-20)
  The cation type was changed as shown in Table 3 below, and the cation and Li⁺And B [(OCO)₂]₂ ⁻And BF₄ ⁻And a molar ratio (cation: Li⁺: B [(OCO)₂]₂ ⁻: BF₄ ⁻) Is as described above except that the mixing is 42: 8: 20: 30.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled. In Table 3, DMPI⁺Represents 1,2-diethyl-3-propylimidazolium ion.
[0121]
(Example 21)
LiFePO as positive electrode active material₄Particles having an average primary particle diameter of 20 nm.₂The particles are 1% by weight with respect to the whole positive electrode, and the graphite powder and the binder are 5% by weight with respect to the whole positive electrode so that the ratio is 8% by weight with respect to the whole positive electrode as a conductive material. And PVdF were respectively blended and dispersed in an n-methylpyrrolidone (NMP) solvent to prepare a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and subjected to a pressing process to an electrode density of 3.3 g / cm.³The positive electrode was obtained.
[0122]
  Except for using this positive electrode, as described above.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0123]
(Comparative Example 4)
MEI⁺And Li⁺And BF₄ ⁻And the molar ratio (MEI⁺: Li⁺: BF₄ ⁻) Was 42: 8: 50, and a room temperature molten salt that was liquid at 20 ° C. was obtained.
[0124]
  As described above, except that this room temperature molten salt is used as a non-aqueous electrolyte.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0125]
(Comparative Example 5)
MEI⁺And Li⁺And N (CF₃SO₂)₂ ⁻And the molar ratio (MEI⁺: Li⁺: N (CF₃SO₂)₂ ⁻) Was 42: 8: 50, and a room temperature molten salt that was liquid at 20 ° C. was obtained.
[0126]
  As described above, except that this room temperature molten salt is used as a non-aqueous electrolyte.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0127]
  (Comparative Example 6)
  The same kind of nonaqueous electrolyte as used in Comparative Example 4,referenceAs described above, except that the same type of negative electrode as used in Example 17 was used.referenceA thin non-aqueous electrolyte secondary battery having the same configuration as described in Example 11 was assembled.
[0128]
  ObtainedreferenceExamples 11-20, ExampleFor the non-aqueous electrolyte secondary batteries of No. 21 and Comparative Examples 4 to 6, a charge / discharge cycle under the charge / discharge conditions described below was performed at 20 ° C., and the initial discharge capacity and cycle life (discharge capacity was 80% of the initial capacity). And the results are shown in Table 3 below.
[0129]
  <Charging / discharging conditions>
  Use lithium aluminum alloy foil as negative electrodereferenceAbout Examples 11-15, 18-20, and Comparative Examples 4 and 5, after charging to 4V with a constant current of 100 mA, a charge / discharge cycle was performed in which a constant current of 100 mA was discharged up to 3V.
[0130]
  Use aluminum metal foil as negative electrodereferenceAbout Example 16, after charging to 3.8V with a constant current of 100 mA, a charge / discharge cycle was performed in which a constant current of 100 mA was discharged to 1.5V.
[0131]
  Use lithium titanate as negative electrode active materialreferenceAbout Example 17 and Comparative Example 6, after charging to 2.5 V with a constant current of 100 mA, a charge / discharge cycle for performing a constant current discharge of 100 mA to 1.5 V was performed.
[0132]
  Also,referenceExamples 11-20, ExampleFor the nonaqueous electrolyte secondary batteries of No. 21 and Comparative Examples 4 to 6, after charging, the batteries were stored at 85 ° C. for 20 days, the remaining capacity was measured (the discharge capacity before storage was 100%), and the results are shown in the following table. 3 shows.
[0133]
[Table 3]

[0134]
  As is clear from Table 3, lithium ions and B [(OCO)₂]₂ ^-A room temperature molten salt containing an anion represented byreferenceExamples 11-20, ExampleThe secondary battery of 21 is B [(OCO)₂]₂ ^-It can be understood that the cycle life is long and the capacity remaining rate at high temperature storage is high as compared with Comparative Examples 4 to 6 without addition.
[0135]
  (referenceExample 22)
  Except for using manganese dioxide particles as positive electrode active material particles,referenceA thin non-aqueous electrolyte primary battery was produced in the same manner as described in Example 11.
[0136]
(Comparative Example 7)
A thin nonaqueous electrolyte primary battery was produced in the same manner as described in Comparative Example 4 except that manganese dioxide particles were used as the positive electrode active material particles.
[0137]
  referenceEach of the nonaqueous electrolyte primary batteries of Example 22 and Comparative Example 7 was divided into two parts, one of which was stored at a high temperature of 85 ° C. for 1000 hours and then subjected to a discharge test at 500 mA. For the other, a discharge test was performed at 500 mA without performing high-temperature storage, and the obtained battery capacity is shown in Table 4 below. Table 4 below shows the discharge capacity after high-temperature storage when the battery capacity is 100%, as the remaining rate during high-temperature storage.
[0138]
[Table 4]

[0139]
  As is clear from Table 4,referenceIt can be understood that the nonaqueous electrolyte primary battery of Example 22 is superior in capacity characteristics and long-term high-temperature storage characteristics as compared with Comparative Example 7.
[0140]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0141]
【The invention's effect】
  As described above in detail, according to the present invention, it is possible to provide a non-aqueous electrolyte battery having a normal temperature molten salt and excellent in large current discharge characteristics..
[Brief description of the drawings]
1 is a partially cutaway perspective view showing a thin nonaqueous electrolyte secondary battery of Example 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrode group, 2 ... Positive electrode, 3 ... Negative electrode, 4 ... Separator, 5 ... Positive electrode terminal, 6 ... Negative electrode terminal, 7 ... Container.

Claims (4)

A non-aqueous electrolyte battery comprising a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte including a room temperature molten salt containing lithium ions,
Wherein at least one electrode of the positive electrode and the negative electrode, Al ₂ O ₃ grains terminal, Zr O ₂ grains Kooyobi Si average primary particle size of at least one O from the group consisting of ₂ tablets element is selected 1 A non-aqueous electrolyte battery comprising metal oxide particles in a range of 100 nm. The metal oxide particles are contained in the positive electrode, and when the average particle size of the active material particles of the positive electrode is D ₁ (nm), particles having the average primary particle size d (nm) with respect to the average particle size D ₁ 2. The nonaqueous electrolyte battery according to claim 1, wherein a diameter ratio (d / D ₁ ) is in a range of 1 × 10 ⁻⁵ to 1 × 10 ⁻¹ . The non-aqueous electrolyte battery according to claim 1 , wherein the negative electrode active material is lithium titanate . The positive electrode active material is lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, spinel type lithium manganese nickel composite oxide, lithium manganese cobalt composite oxide, lithium phosphoric acid iron, manganese dioxide, iron oxide, copper oxide, a non-aqueous electrolyte battery of claim 1 any one of claims, characterized in that at least one selected from iron sulfide, and carbon fluoride.

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