JP2022139980A - Recovery agent, recovery method for non-aqueous electrolyte secondary battery, and manufacturing method for non-aqueous electrolyte secondary battery - Google Patents
Recovery agent, recovery method for non-aqueous electrolyte secondary battery, and manufacturing method for non-aqueous electrolyte secondary battery Download PDFInfo
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- JP2022139980A JP2022139980A JP2021040590A JP2021040590A JP2022139980A JP 2022139980 A JP2022139980 A JP 2022139980A JP 2021040590 A JP2021040590 A JP 2021040590A JP 2021040590 A JP2021040590 A JP 2021040590A JP 2022139980 A JP2022139980 A JP 2022139980A
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- aqueous electrolyte
- secondary battery
- electrolyte secondary
- recovery
- recovery agent
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Abstract
Description
本開示は、回復剤、非水電解液二次電池の回復方法及び非水電解液二次電池の製造方法に関する。 The present disclosure relates to a recovery agent, a recovery method for a non-aqueous electrolyte secondary battery, and a method for manufacturing a non-aqueous electrolyte secondary battery.
従来、長期保存や充放電サイクルによって容量が劣化した非水電解液二次電池の容量を回復させる方法として、正極及び負極の他に第三極を設け、第三極と正極とを外部短絡させ、第三極から正極にキャリアイオンを供給する方法が提案されている（例えば、特許文献１参照）。 Conventionally, as a method for recovering the capacity of a non-aqueous electrolyte secondary battery whose capacity has deteriorated due to long-term storage or charge-discharge cycles, a third electrode is provided in addition to the positive electrode and the negative electrode, and the third electrode and the positive electrode are externally short-circuited. , a method of supplying carrier ions from the third electrode to the positive electrode has been proposed (see, for example, Patent Document 1).
しかしながら、特許文献１では、第三極を組み入れることにより、電池の構造が複雑になるなどの問題があった。このため、第三極を用いなくても容量を回復させることのできる、非水電解液二次電池の新規な回復方法が望まれていた。
However, in
本開示はこのような課題を解決するためになされたものであり、非水電解液二次電池の新規な回復方法を提供することを主目的とする。 The present disclosure has been made to solve such problems, and a main object thereof is to provide a novel recovery method for a non-aqueous electrolyte secondary battery.
上述した目的を達成するために鋭意研究したところ、本発明者らは、還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、この溶質を溶解する溶媒と、を含む溶液を非水電解液二次電池に注入すると、容量が回復することを見出した。特に、回復剤において、上述の溶質及び溶媒のほかに、例えば非水電解液二次電池に用いられるような電解液を含むものとすると、回復後の電池の容量がより向上することを見出し、本開示を完成するに至った。 As a result of intensive research to achieve the above object, the present inventors found that a solution containing a solute having a reduced aromatic hydrocarbon compound and metal ions and a solvent for dissolving this solute is prepared as a non-aqueous solution. It was found that the capacity was recovered by injecting it into an electrolytic solution secondary battery. In particular, it was found that if the recovery agent contains, in addition to the above-mentioned solute and solvent, an electrolytic solution such as that used in non-aqueous electrolyte secondary batteries, the capacity of the battery after recovery is further improved. I have completed the disclosure.
即ち、本明細書で開示する回復剤は、
金属イオンをキャリアイオンとする非水電解液二次電池の容量を回復させる回復剤であって、
還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、前記溶質を溶解する溶媒と、電解液と、を含む、
ものである。
That is, the recovery agents disclosed herein are
A recovery agent for recovering the capacity of a non-aqueous electrolyte secondary battery using metal ions as carrier ions,
comprising a solute having an aromatic hydrocarbon compound in a reduced state and a metal ion, a solvent that dissolves the solute, and an electrolytic solution;
It is.
また、本明細書で開示する非水電解液二次電池の回復方法は、
金属イオンをキャリアイオンとする非水電解液二次電池の容量を回復させる回復方法であって、
前記非水電解液二次電池に対して、上述した回復剤を注入して、前記非水電解液二次電池の容量を回復させる回復工程、
を含むものである。
In addition, the recovery method for the non-aqueous electrolyte secondary battery disclosed in this specification includes:
A recovery method for recovering the capacity of a non-aqueous electrolyte secondary battery using metal ions as carrier ions,
A recovery step of injecting the recovery agent described above into the non-aqueous electrolyte secondary battery to recover the capacity of the non-aqueous electrolyte secondary battery;
includes.
また、本明細書で開示する非水電解液二次電池の製造方法は、
金属イオンをキャリアイオンとする容量劣化した非水電解液二次電池を準備する電池準備工程と、
上述の非水電解液二次電池の回復方法で前記非水電解液二次電池の容量を回復させる回復工程と、
を含むものである。
Further, the method for manufacturing the non-aqueous electrolyte secondary battery disclosed in this specification includes:
A battery preparation step of preparing a non-aqueous electrolyte secondary battery with metal ions as carrier ions and having deteriorated capacity;
a recovery step of recovering the capacity of the non-aqueous electrolyte secondary battery by the recovery method for the non-aqueous electrolyte secondary battery described above;
includes.
この回復剤、非水電解液二次電池の回復方法及び非水電解液二次電池の製造方法では、非水電解液二次電池の新規な回復方法及びそれを利用した非水電解液二次電池の新規な製造方法を提供できる。このような効果が得られる理由は以下のように推察される。例えば、還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、この溶質を溶解する溶媒と、を含む回復剤は、非水電解液二次電池に注入するだけで正極に直接作用して、正極に電子と金属イオンを供給する回復反応を生じるためと推察される。特に、上述の溶質と溶媒のほかに、電解液を含む回復剤では、回復後の電池の容量がより向上する。この理由は以下のように推察される。例えば、電解液を含む回復剤では、電解液を含まない回復剤より、芳香族炭化水素化合物に対する溶媒和が大きく、還元状態の芳香族炭化水素化合物が金属イオンを離しやすい。このため、電解液を含む回復剤を用いると、正極に電子と金属イオンが供給される際の活性化エネルギーが小さくなり、正極への電子と金属イオンの供給が円滑に行われ、効率良く回復反応が進行して、回復後の電池の容量がより向上すると考えられる。 This recovery agent, recovery method for non-aqueous electrolyte secondary batteries, and method for manufacturing non-aqueous electrolyte secondary batteries provide a novel recovery method for non-aqueous electrolyte secondary batteries and a non-aqueous electrolyte secondary battery using the same. A novel method for manufacturing a battery can be provided. The reason why such an effect is obtained is presumed as follows. For example, a recovery agent containing a solute having a reduced aromatic hydrocarbon compound and metal ions and a solvent for dissolving this solute acts directly on the positive electrode simply by being injected into the non-aqueous electrolyte secondary battery. This is presumed to be due to a recovery reaction that supplies electrons and metal ions to the positive electrode. In particular, a recovery agent containing an electrolytic solution in addition to the above-described solute and solvent further improves the capacity of the battery after recovery. The reason for this is presumed as follows. For example, a recovery agent containing an electrolyte has a higher solvation with respect to an aromatic hydrocarbon compound than a recovery agent that does not contain an electrolyte, and the reduced aromatic hydrocarbon compound easily separates metal ions. Therefore, when a recovery agent containing an electrolytic solution is used, the activation energy when electrons and metal ions are supplied to the positive electrode becomes small, and the supply of electrons and metal ions to the positive electrode is performed smoothly, resulting in efficient recovery. It is thought that the reaction progresses and the capacity of the battery after recovery is further improved.
本明細書で開示する回復剤は、非水電解液二次電池の容量を回復させるものである。また、本明細書で開示する非水電解液二次電池の回復方法は、非水電解液二次電池の容量を回復させる方法である。回復剤及び非水電解液二次電池の回復方法の好適な実施形態について以下に説明する。 The recovery agent disclosed in this specification recovers the capacity of a non-aqueous electrolyte secondary battery. A recovery method for a non-aqueous electrolyte secondary battery disclosed in this specification is a method for recovering the capacity of a non-aqueous electrolyte secondary battery. Preferred embodiments of the recovery agent and the recovery method of the non-aqueous electrolyte secondary battery will be described below.
［非水電解液二次電池］
まず、回復対象の非水電解液二次電池について説明する。非水電解液二次電池は、金属イオンをキャリアイオンとする非水電解液二次電池であることが好ましい。非水電解液二次電池は、例えば、リチウム、ナトリウム、カリウムなどの第１族イオンや、マグネシウム、カルシウム、ストロンチウムなどの第２族イオンをキャリアイオンとするものとしてもよい。また、非水電解液二次電池は、リチウムイオン二次電池などのイオン二次電池としてもよいし、リチウム金属二次電池などの金属二次電池としてもよい。以下では、一例として、非水電解液二次電池がリチウムイオン二次電池である場合について主に説明する。
[Non-aqueous electrolyte secondary battery]
First, the non-aqueous electrolyte secondary battery to be recovered will be described. The non-aqueous electrolyte secondary battery is preferably a non-aqueous electrolyte secondary battery using metal ions as carrier ions. The non-aqueous electrolyte secondary battery may use, for example,
非水電解液二次電池は、正極と、負極と、非水電解液とを備えている。正極は、リチウムイオンを吸蔵、放出しうる正極活物質を有するものとしてもよい。負極は、リチウムイオンを吸蔵・放出しうる負極活物質を有するものとしてもよい。非水電解液は、正極と負極との間に介在しリチウムイオンを伝導するものとしてもよい。 A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode may have a positive electrode active material capable of intercalating and deintercalating lithium ions. The negative electrode may have a negative electrode active material capable of intercalating and deintercalating lithium ions. The non-aqueous electrolyte may be interposed between the positive electrode and the negative electrode to conduct lithium ions.
正極は、例えば正極活物質と導電材と結着材とを混合し、適当な溶剤を加えてペースト状の正極合材としたものを、集電体の表面に塗布乾燥し、必要に応じて電極密度を高めるべく圧縮して形成してもよい。正極活物質としては、遷移金属元素を含む硫化物や、リチウムと遷移金属元素とを含む酸化物などを用いることができる。具体的には、ＴｉＳ2、ＴｉＳ3、ＭｏＳ3、ＦｅＳ2などの遷移金属硫化物、基本組成式をＬｉ(1-x)ＭｎＯ2（０＜ｘ＜１など、以下同じ）やＬｉ(1-x)Ｍｎ2Ｏ4などとするリチウムマンガン複合酸化物、基本組成式をＬｉ(1-x)ＣｏＯ2などとするリチウムコバルト複合酸化物、基本組成式をＬｉ(1-x)ＮｉＯ2などとするリチウムニッケル複合酸化物、基本組成式をＬｉ(1-x)ＮｉaＣｏbＭｎcＯ2（ａ＋ｂ＋ｃ＝１）などとするリチウムニッケルコバルトマンガン複合酸化物、基本組成式をＬｉＶ2Ｏ3などとするリチウムバナジウム複合酸化物、基本組成式をＶ2Ｏ5などとする遷移金属酸化物などを用いることができる。これらのうち、リチウムの遷移金属複合酸化物、例えば、ＬｉＣｏＯ2、ＬｉＮｉＯ2、ＬｉＭｎＯ2、ＬｉＶ2Ｏ3などが好ましい。また、ＬｉyＮｉ(1-x)ＭxＯ2（ただし、０≦ｘ≦０．５、０＜ｙ＜１．２０、ＭはＣｏ、Ａｌ、Ｍｎ、Ｆｅ、Ｔｉ及びＢからなる群より選ばれる少なくとも１種の元素）も好ましく、これにスピネル構造を有するリチウムマンガン複合酸化物を組み合わせて用いてもよい。なお、「基本組成式」とは、他の元素を含んでもよい趣旨である。正極活物質は、酸化還元電位が、Ｌｉ金属基準で３．５Ｖ以上のものとしてもよく、４．０Ｖ以上のものとしてもよく、４．５Ｖ以上のものとしてもよい。
For the positive electrode, for example, a positive electrode active material, a conductive material, and a binder are mixed, and an appropriate solvent is added to make a paste-like positive electrode mixture. It may be formed by compression in order to increase the electrode density. A sulfide containing a transition metal element, an oxide containing lithium and a transition metal element, or the like can be used as the positive electrode active material. Specifically, transition metal sulfides such as TiS 2 , TiS 3 , MoS 3 and FeS 2 , and basic compositional formulas of Li (1-x) MnO 2 (0<x<1, etc., the same applies hereinafter) and Li (1 -x) Lithium-manganese composite oxides such as Mn 2 O 4 , Lithium-cobalt composite oxides such as Li (1-x) CoO 2 with a basic composition formula, Li (1-x) NiO 2 with a basic composition formula, etc. a lithium-nickel composite oxide having a basic composition formula of Li (1-x) Ni a Co b Mn c O 2 (a+b+c=1) or the like, a basic composition formula of LiV 2 O 3 Lithium vanadium composite oxides such as V 2
正極において、導電材は、例えば、天然黒鉛（鱗状黒鉛、鱗片状黒鉛）や人造黒鉛などの黒鉛、アセチレンブラック、カーボンブラック、ケッチェンブラック、カーボンウィスカ、ニードルコークス、炭素繊維、金属（銅、ニッケル、アルミニウム、銀、金など）などの１種又は２種以上を混合したものを用いることができる。これらの中で、導電材としては、電子伝導性及び塗工性の観点より、カーボンブラック及びアセチレンブラックが好ましい。結着材は、活物質粒子及び導電材粒子を繋ぎ止める役割を果たすものであり、例えば、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶｄＦ）、フッ素ゴム等の含フッ素樹脂、或いはポリプロピレン、ポリエチレン等の熱可塑性樹脂、エチレンプロピレンジエンモノマー（ＥＰＤＭ）ゴム、スルホン化ＥＰＤＭゴム、天然ブチルゴム（ＮＢＲ）等を単独で、あるいは２種以上の混合物として用いることができる。また、水系バインダーであるセルロース系のカルボキシメチルセルロース（ＣＭＣ）やスチレンブタジエン共重合体（ＳＢＲ）、ポリビニルアルコールなどの水分散体等を用いることもできる。正極活物質、導電材、結着材を分散させる溶剤としては、例えばＮ－メチルピロリドン、ジメチルホルムアミド、ジメチルアセトアミド、メチルエチルケトン、シクロヘキサノン、酢酸メチル、アクリル酸メチル、ジエチレントリアミン、Ｎ，Ｎ－ジメチルアミノプロピルアミン、エチレンオキシド、テトラヒドロフランなどの有機溶剤を用いることができる。また、水に分散剤、増粘剤等を加え、ＳＢＲなどのラテックスで活物質をスラリー化してもよい。増粘剤としては、例えば、カルボキシメチルセルロース、メチルセルロースなどの多糖類を単独で、あるいは２種以上の混合物として用いることができる。塗布方法としては、例えば、アプリケータロールなどのローラコーティング、スクリーンコーティング、ドクターブレイド方式、スピンコーティング、バーコータなどが挙げられ、これらのいずれかを用いて任意の厚さ・形状とすることができる。正極合材の目付量は、特に限定されるものではないが、例えば、５ｍｇ／ｃｍ2超過としてもよく、６ｍｇ／ｃｍ2以上としてもよく、７ｍｇ／ｃｍ2以上としてもよい。正極合材の目付量は、例えば、２０ｍｇ／ｃｍ2以下としてもよい。集電体としては、アルミニウム、チタン、ステンレス鋼、ニッケル、鉄、焼成炭素、導電性高分子、導電性ガラスなどのほか、接着性、導電性及び耐酸化性向上の目的で、アルミニウムや銅などの表面をカーボン、ニッケル、チタンや銀などで処理したものを用いることができる。これらについては、表面を酸化処理することも可能である。集電体の形状については、箔状、フィルム状、シート状、ネット状、パンチ又はエキスパンドされたもの、ラス体、多孔質体、発泡体、繊維群の形成体などが挙げられる。集電体の厚さは、例えば１～５００μｍのものが用いられる。 In the positive electrode, the conductive material is, for example, graphite such as natural graphite (scale graphite, scale graphite) or artificial graphite, acetylene black, carbon black, ketjen black, carbon whisker, needle coke, carbon fiber, metal (copper, nickel , aluminum, silver, gold, etc.) or a mixture of two or more thereof can be used. Among these, carbon black and acetylene black are preferable as the conductive material from the viewpoint of electronic conductivity and coatability. The binder plays a role of binding the active material particles and the conductive material particles, and examples thereof include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-containing resin such as fluororubber, polypropylene, Thermoplastic resins such as polyethylene, ethylene propylene diene monomer (EPDM) rubber, sulfonated EPDM rubber, natural butyl rubber (NBR) and the like can be used alone or as a mixture of two or more. In addition, an aqueous dispersion of cellulose-based carboxymethyl cellulose (CMC), styrene-butadiene copolymer (SBR), polyvinyl alcohol, or the like, which is an aqueous binder, can also be used. Examples of solvents for dispersing the positive electrode active material, conductive material, and binder include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methylethylketone, cyclohexanone, methyl acetate, methyl acrylate, diethylenetriamine, and N,N-dimethylaminopropylamine. , ethylene oxide, and tetrahydrofuran can be used. Alternatively, a dispersant, a thickener, or the like may be added to water, and the active material may be slurried with a latex such as SBR. As the thickening agent, for example, polysaccharides such as carboxymethyl cellulose and methyl cellulose can be used singly or as a mixture of two or more. Application methods include, for example, roller coating such as applicator roll, screen coating, doctor blade method, spin coating, and bar coater, and any thickness and shape can be obtained using any of these methods. The basis weight of the positive electrode mixture is not particularly limited, but may be, for example, more than 5 mg/cm 2 , 6 mg/cm 2 or more, or 7 mg/cm 2 or more. The basis weight of the positive electrode mixture may be, for example, 20 mg/cm 2 or less. Current collectors include aluminum, titanium, stainless steel, nickel, iron, calcined carbon, conductive polymer, and conductive glass. The surface of which is treated with carbon, nickel, titanium, silver, or the like can be used. For these, it is also possible to oxidize the surface. Examples of the shape of the current collector include foil, film, sheet, net, punched or expanded, lath, porous, foam, and fiber group formations. The current collector used has a thickness of, for example, 1 to 500 μm.
負極は、負極活物質と集電体とを密着させて形成したものとしてもよいし、例えば負極活物質と導電材と結着材とを混合し、適当な溶剤を加えてペースト状の負極合材としたものを、集電体の表面に塗布乾燥し、必要に応じて電極密度を高めるべく圧縮して形成してもよい。負極活物質としては、リチウム、リチウム合金、スズ化合物などの無機化合物、リチウムイオンを吸蔵・放出可能な炭素質材料、複数の元素を含む複合酸化物、導電性ポリマーなどが挙げられる。炭素質材料は、例えば、コークス類、ガラス状炭素類、グラファイト類、難黒鉛化性炭素類、熱分解炭素類、炭素繊維、非晶質炭素、ダイヤモンド状炭素、フラーレン、カーボンナノチューブ、カーボンナノホーンなどが挙げられる。このうち、人造黒鉛、天然黒鉛などのグラファイト類が、金属リチウムに近い作動電位を有し、高い作動電圧での充放電が可能であり支持塩としてリチウム塩を使用した場合に自己放電を抑え、且つ充電時における不可逆容量を少なくできるため、好ましい。複合酸化物としては、例えば、リチウムチタン複合酸化物やリチウムバナジウム複合酸化物などが挙げられる。負極活物質としては、このうち、炭素質材料が安全性の面から見て好ましい。また、負極に用いられる導電材、結着材、溶剤などは、それぞれ正極で例示したものを用いることができる。負極活物質は、酸化還元電位が、Ｌｉ金属基準で１．０Ｖ以下のものとしてもよく、０．５Ｖ以下のものとしてもよく、０．３Ｖ以下のものとしてもよい。負極合材の目付量は、例えば、３ｍｇ／ｃｍ2超過としてもよく、４ｍｇ／ｃｍ2以上としてもよい。負極合材の目付量は、例えば、１５ｍｇ／ｃｍ2以下としてもよい。負極の集電体には、銅、ニッケル、ステンレス鋼、チタン、アルミニウム、焼成炭素、導電性高分子、導電性ガラス、Ａｌ－Ｃｄ合金などのほか、接着性、導電性及び耐還元性向上の目的で、例えば銅などの表面をカーボン、ニッケル、チタンや銀などで処理したものも用いることができる。これらについては、表面を酸化処理することも可能である。集電体の形状は、正極と同様のものを用いることができる。 The negative electrode may be formed by adhering a negative electrode active material and a current collector. The material may be coated on the surface of the current collector, dried, and compressed to increase the electrode density, if necessary. Examples of negative electrode active materials include inorganic compounds such as lithium, lithium alloys and tin compounds, carbonaceous materials capable of intercalating and deintercalating lithium ions, composite oxides containing multiple elements, and conductive polymers. Examples of carbonaceous materials include cokes, glassy carbons, graphites, non-graphitizable carbons, pyrolytic carbons, carbon fibers, amorphous carbon, diamond-like carbon, fullerenes, carbon nanotubes, carbon nanohorns, and the like. is mentioned. Among them, graphites such as artificial graphite and natural graphite have an operating potential close to that of metallic lithium, can be charged and discharged at a high operating voltage, and suppress self-discharge when lithium salt is used as a supporting salt. Moreover, the irreversible capacity during charging can be reduced, which is preferable. Examples of composite oxides include lithium-titanium composite oxides and lithium-vanadium composite oxides. Among them, carbonaceous materials are preferable as the negative electrode active material from the viewpoint of safety. As the conductive material, binder, solvent, and the like used for the negative electrode, those exemplified for the positive electrode can be used. The negative electrode active material may have an oxidation-reduction potential of 1.0 V or less, 0.5 V or less, or 0.3 V or less based on Li metal. The basis weight of the negative electrode mixture may, for example, exceed 3 mg/cm 2 or may be 4 mg/cm 2 or more. The basis weight of the negative electrode mixture may be, for example, 15 mg/cm 2 or less. The current collector of the negative electrode includes copper, nickel, stainless steel, titanium, aluminum, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, etc. For that purpose, for example, copper or the like whose surface is treated with carbon, nickel, titanium, silver, or the like can also be used. For these, it is also possible to oxidize the surface. A current collector having the same shape as that of the positive electrode can be used.
非水電解液は、支持塩と有機溶媒とを含むものとしてもよい。支持塩としては、例えば、ＬｉＰＦ6、ＬｉＣｌＯ4、ＬｉＡｓＦ6、ＬｉＡｌＣｌ4、ＬｉＢＦ4、ＬｉＳｂＦ6などの無機塩や、ＬｉＮ（ＦＳＯ2）2（ＬｉＦＳＩとも称する）、ＬｉＮ（ＣＦ3ＳＯ2）2（ＬｉＴＦＳＩとも称する）、ＬｉＮ（Ｃ2Ｆ5ＳＯ2）2（ＬｉＢＥＴＩとも称する）などの有機塩が挙げられる。これらの支持塩は、単独で用いてもよいし、複数を組み合わせて用いてもよい。支持塩の濃度は、０．１～２．０Ｍであることが好ましく、０．８～１．２Ｍであることがより好ましい。有機溶媒としては、例えば、非プロトン性の有機溶媒を用いることができる。このような有機溶媒としては、例えば環状カーボネート、鎖状カーボネート、環状エステル、環状エーテル、鎖状エーテル、これらのフッ化誘導体等が挙げられる。環状カーボネートとしては、例えばエチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネート等がある。鎖状カーボネートとしては、例えばジメチルカーボネート、ジエチルカーボネート、メチルエチルカーボネート等がある。環状エステルとしては、例えばガンマブチロラクトン、ガンマバレロラクトン等がある。環状エーテルとしては、例えばテトラヒドロフラン、２－メチルテトラヒドロフラン等がある。鎖状エーテルとしては、例えばジメトキシエタン、エチレングリコールジメチルエーテル等がある。これらは単独で用いてもよいし、複数を混合して用いてもよい。また、非水電解液としては、そのほかにアセトニトリル、プロピルニトリルなどのニトリル系溶媒やイオン液体、ゲル電解質などを用いてもよい。非水電解液は、例えば、被膜形成剤や難燃剤等の添加剤を含んでいてもよい。 The non-aqueous electrolyte may contain a supporting salt and an organic solvent. Examples of supporting electrolytes include inorganic salts such as LiPF 6 , LiClO 4 , LiAsF 6 , LiAlCl 4 , LiBF 4 and LiSbF 6 , LiN(FSO 2 ) 2 (also referred to as LiFSI) and LiN(CF 3 SO 2 ) 2 . (also called LiTFSI) and LiN( C2F5SO2 ) 2 ( also called LiBETI ). These supporting salts may be used alone or in combination. The concentration of the supporting salt is preferably 0.1-2.0M, more preferably 0.8-1.2M. As the organic solvent, for example, an aprotic organic solvent can be used. Examples of such organic solvents include cyclic carbonates, chain carbonates, cyclic esters, cyclic ethers, chain ethers, and fluorinated derivatives thereof. Cyclic carbonates include, for example, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, and the like. Examples of chain carbonates include dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate. Cyclic esters include, for example, gamma-butyrolactone and gamma-valerolactone. Cyclic ethers include, for example, tetrahydrofuran and 2-methyltetrahydrofuran. Chain ethers include, for example, dimethoxyethane and ethylene glycol dimethyl ether. These may be used alone, or may be used in combination. In addition, as the nonaqueous electrolyte, nitrile solvents such as acetonitrile and propylnitrile, ionic liquids, gel electrolytes, and the like may be used. The non-aqueous electrolyte may contain additives such as film-forming agents and flame retardants.
非水電解液二次電池は、正極と負極との間にセパレータを備えていてもよい。セパレータとしては、非水電解液二次電池の使用範囲に耐えうる組成であれば特に限定されないが、例えば、ポリプロピレン製不織布やポリフェニレンスルフィド製不織布などの高分子不織布、ポリエチレンやポリプロピレンなどのオレフィン系樹脂やフッ素樹脂などの薄い微多孔膜が挙げられる。これらは単独で用いてもよいし、複数を混合して用いてもよい。 The non-aqueous electrolyte secondary battery may have a separator between the positive electrode and the negative electrode. The separator is not particularly limited as long as it has a composition that can withstand the range of use of the non-aqueous electrolyte secondary battery. and thin microporous membranes such as fluororesins. These may be used alone, or may be used in combination.
非水電解液二次電池は、正極、負極及び非水電解液を収容する電池ケースに、開閉可能な注液口を有していてもよい。注液口から容易に回復剤を注入できる。 The non-aqueous electrolyte secondary battery may have an openable and closable pouring port in a battery case containing the positive electrode, the negative electrode and the non-aqueous electrolyte. The recovery agent can be easily injected from the injection port.
非水電解液二次電池の形状は、特に限定されないが、例えばコイン型、ボタン型、シート型、積層型、円筒型、偏平型、角型などが挙げられる。また、電気自動車等に用いる大型のものなどに適用してもよい。図１は、非水電解液二次電池２０の一例を示す模式図である。この非水電解液二次電池２０は、カップ形状の電池ケース２１と、正極活物質を有しこの電池ケース２１の下部に設けられた正極２２と、負極活物質を有し正極２２に対してセパレータ２４を介して対向する位置に設けられた負極２３と、絶縁材により形成されたガスケット２５と、電池ケース２１の開口部に配設されガスケット２５を介して電池ケース２１を密封する封口板２６と、を備えている。この非水電解液二次電池２０では、正極２２と負極２３との間の空間に非水電解液２７が満たされている。
The shape of the non-aqueous electrolyte secondary battery is not particularly limited, and examples thereof include coin type, button type, sheet type, laminated type, cylindrical type, flat type, and rectangular type. Also, it may be applied to a large-sized one used for an electric vehicle or the like. FIG. 1 is a schematic diagram showing an example of a non-aqueous electrolyte
非水電解液二次電池は、容量劣化していない状態の電池（劣化前電池とも称する）において、内部抵抗が５Ωｃｍ2超過であるものとしてもよく、７Ωｃｍ2以上であるものとしてもよく、１０Ωｃｍ2以上であるものとしてもよい。電気自動車用の電池など、電極合材の厚みや目付量が大きく、内部抵抗が比較的大きい非水電解液二次電池では、回復剤を注入するだけでは、回復後の電池の容量及びサイクル容量維持率が低いことが多いため、本開示の非水電解液二次電池の回復方法を適用する意義が高い。なお、劣化前電池の内部抵抗は、５０Ωｃｍ2以下であるものとしてもよい。 The non-aqueous electrolyte secondary battery may have an internal resistance exceeding 5 Ωcm 2 , 7 Ωcm 2 or more, or 10 Ωcm in a state where the capacity is not deteriorated (also referred to as a battery before deterioration). It may be 2 or more. In non-aqueous electrolyte secondary batteries, such as batteries for electric vehicles, where the thickness of the electrode mixture and weight per unit area are large and the internal resistance is relatively high, the capacity and cycle capacity of the battery after recovery cannot be reduced by simply injecting the recovery agent. Since the retention rate is often low, it is highly significant to apply the recovery method of the non-aqueous electrolyte secondary battery of the present disclosure. The internal resistance of the battery before deterioration may be 50 Ωcm 2 or less.
［回復剤］
次に、回復剤について説明する。回復剤は、還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、この溶質を溶解する溶媒と、電解液とを含む。回復剤は、予め調製された回復剤でもよいし、回復剤を調製する調製工程で調製してもよい。回復剤において、還元状態の芳香族炭化水素化合物と金属イオンとは、解離していてもよいし、会合していてもよい。
[Restoration agent]
Next, the recovery agent will be explained. The recovery agent includes a solute having a reduced aromatic hydrocarbon compound and metal ions, a solvent that dissolves the solute, and an electrolytic solution. The restorative agent may be a pre-prepared restorative agent or may be prepared in the preparation step of preparing the restorative agent. In the recovery agent, the reduced aromatic hydrocarbon compound and the metal ion may be dissociated or associated.
回復剤において、芳香族炭化水素化合物は、ポリアセン又はポリフェニルであることが好ましい。ポリアセンは複数のベンゼン環が縮合した構造を有する化合物であり、ナフタレン、アントラセン、テトラセン、ペンタセン等が挙げられる。ポリフェニルは複数のフェニル基が単結合により連結した構造を有する化合物であり、ビフェニル、オルトターフェニル、メタターフェニル、パラターフェニル、パラクアテルフェニル、パラキンキフェニル等が挙げられる。ポリアセンやポリフェニルは、芳香環上に置換基を有していてもよいし、芳香環内にヘテロ原子を含んでいてもよい。置換基としては、例えば、ハロゲン原子、アルキル基、アリール基、アルケニル基、アルコキシ基、アリールオキシ基、スルホニル基、アミノ基、シアノ基、カルボニル基、アシル基、アミド基、水酸基等が挙げられる。ヘテロ原子としては、窒素、酸素、硫黄などが挙げられる。芳香環内にヘテロ原子を含むポリアセンとしては、キノリン、クロメン、アクリジンなどが挙げられる。芳香環内にヘテロ原子を含むポリフェニルとしては、ビピリジンなどが挙げられる。芳香族炭化水素化合物は、上述したもののほか、例えば、シクロヘキシルベンゼン等、芳香環にシクロアルカンが結合した化合物であることも好ましい。芳香族炭化水素化合物は、上述したもののうち、ナフタレン、ビフェニル、アントラセン、オルトターフェニル、パラターフェニルのうち１以上であることが好ましく、ナフタレン及びビフェニルのうちの１以上であることがより好ましい。芳香族炭化水素化合物は、例えば、式（１）及び式（２）のうちの１以上としてもよい。還元状態の芳香族炭化水素化合物は、例えば上述の芳香族炭化水素化合物が還元された状態のもの（還元体とも称する）であり、例えばラジカルアニオンである。還元状態の芳香族炭化水素化合物は、例えば、式（１）の化合物の還元体及び式（２）の化合物の還元体のうちの１以上としてもよい。 In the restorative agent, the aromatic hydrocarbon compound is preferably polyacene or polyphenyl. Polyacene is a compound having a structure in which a plurality of benzene rings are condensed, and includes naphthalene, anthracene, tetracene, pentacene, and the like. Polyphenyl is a compound having a structure in which a plurality of phenyl groups are linked by single bonds, and includes biphenyl, ortho-terphenyl, meta-terphenyl, para-terphenyl, paraquaterphenyl, paraquinkiphenyl and the like. Polyacene and polyphenyl may have a substituent on the aromatic ring and may contain a heteroatom in the aromatic ring. Examples of substituents include halogen atoms, alkyl groups, aryl groups, alkenyl groups, alkoxy groups, aryloxy groups, sulfonyl groups, amino groups, cyano groups, carbonyl groups, acyl groups, amide groups, and hydroxyl groups. Heteroatoms include nitrogen, oxygen, sulfur, and the like. Polyacenes containing heteroatoms in the aromatic ring include quinolines, chromenes, acridines, and the like. Polyphenyls containing heteroatoms in the aromatic ring include bipyridine and the like. In addition to those mentioned above, the aromatic hydrocarbon compound is preferably a compound in which a cycloalkane is bonded to an aromatic ring, such as cyclohexylbenzene. The aromatic hydrocarbon compound is preferably at least one of naphthalene, biphenyl, anthracene, ortho-terphenyl, and para-terphenyl, and more preferably at least one of naphthalene and biphenyl. The aromatic hydrocarbon compound may be, for example, one or more of formula (1) and formula (2). The aromatic hydrocarbon compound in a reduced state is, for example, the above-described aromatic hydrocarbon compound in a reduced state (also referred to as a reductant), such as a radical anion. The aromatic hydrocarbon compound in a reduced state may be, for example, one or more of the reductant of the compound of formula (1) and the reductant of the compound of formula (2).
回復剤において、金属イオンは、特に限定されるものではないが、例えば、非水電解液二次電池のキャリアイオンと同種の金属イオンとしてもよい。回復剤において、金属イオンは、例えば、リチウムイオン、ナトリウムイオン及びカリウムイオンなどのアルカリ金属イオンや、マグネシウムイオン、カルシウムイオン、ストロンチウムイオンなどのアルカリ土類金属のうち１以上としてもよい。 In the recovery agent, the metal ion is not particularly limited, but may be, for example, the same kind of metal ion as the carrier ion of the non-aqueous electrolyte secondary battery. In the recovery agent, the metal ions may be, for example, one or more of alkali metal ions such as lithium ions, sodium ions and potassium ions, and alkaline earth metal ions such as magnesium ions, calcium ions and strontium ions.
回復剤は、溶質として、式（３）及び式（４）のうちの１以上の化合物を含むものとしてもよい。式（３）及び式（４）の化合物において、ラジカルアニオンの部分が上述の還元状態の芳香族炭化水素化合物であり、金属カチオンの部分が上述の金属イオンである。 The restorative agent may contain one or more compounds of Formula (3) and Formula (4) as a solute. In the compounds of formulas (3) and (4), the radical anion portion is the above-described reduced aromatic hydrocarbon compound, and the metal cation portion is the above-described metal ion.
回復剤において、溶媒は、上述した溶質を溶解するものであり、常温で液体であるものが好ましい。溶媒としては、例えばエーテル化合物などの非プロトン性溶媒が挙げられる。エーテル化合物は、エーテル骨格を有する化合物であればよく、環状エーテルでも鎖状エーテルでもよい。エーテル化合物は、分子内に２以上のエーテル基を有するものが好ましい。溶媒は、テトラヒドロフラン（ＴＨＦ）、ジメトキシエタン（ＤＭＥ）、ジエトキシエタン（ＤＥＥ）、ジオキソラン（ＤＯＬ）、ジオキサン（ＤＯＸ）のうち１以上としてもよい。溶媒は、テトラヒドロフラン及びジメトキシエタンのうちの１以上であることが好ましい。 In the recovery agent, the solvent dissolves the above-described solute, and is preferably liquid at room temperature. Solvents include, for example, aprotic solvents such as ether compounds. The ether compound may be any compound having an ether skeleton, and may be either a cyclic ether or a chain ether. The ether compound preferably has two or more ether groups in its molecule. The solvent may be one or more of tetrahydrofuran (THF), dimethoxyethane (DME), diethoxyethane (DEE), dioxolane (DOL), dioxane (DOX). Preferably, the solvent is one or more of tetrahydrofuran and dimethoxyethane.
回復剤は、溶媒中に、芳香族炭化水素化合物と、イオン状態ではなく金属状態の金属とを投入して得られたものとしてもよい。例えば、式（５）及び式（６）のうちの１以上により得られたものとしてもよい。より具体的には、式（７）～（９）のように、ＴＨＦ溶媒中で、ナフタレン、ジフェニル、ターフェニルとＬｉ金属とを反応させたものとしてもよい。また、式（７）～（９）に準じて、ＤＭＥ溶媒中で、ナフタレン、ジフェニル、ターフェニルとＬｉ金属とを反応させたものとしてもよい。こうすれば、還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、この溶質を溶解する溶媒と、を含む回復剤を容易に調製できる。回復剤は、溶媒に芳香族炭化水素化合物を投入して得られた前駆体に、金属を投入して調製してもよい。回復剤は、アルゴン雰囲気や窒素雰囲気などの不活性雰囲気下で調製してもよい。回復剤は、露点が－２０℃以下や、－４０℃以下、－６０℃以下などの低露点環境下で調製してもよい。回復剤は、溶媒と芳香族炭化水素化合物と金属とを撹拌して調製してもよく、その際、スターラーなどを用いてもよい。溶媒は、蒸留やモレキュラーシーブスへの浸漬などにより脱水を行い、水分を１００ｐｐｍ以下にして用いることが好ましい。 The recovery agent may be obtained by adding an aromatic hydrocarbon compound and a metal in a metallic state instead of an ionic state into a solvent. For example, it may be obtained by one or more of formulas (5) and (6). More specifically, as shown in formulas (7) to (9), naphthalene, diphenyl, or terphenyl may be reacted with Li metal in a THF solvent. Further, according to the formulas (7) to (9), naphthalene, diphenyl, terphenyl and Li metal may be reacted in a DME solvent. This makes it possible to easily prepare a recovery agent containing a solute having a reduced aromatic hydrocarbon compound and metal ions and a solvent for dissolving this solute. The recovery agent may be prepared by adding a metal to a precursor obtained by adding an aromatic hydrocarbon compound to a solvent. The recovery agent may be prepared under an inert atmosphere such as an argon atmosphere or a nitrogen atmosphere. The recovery agent may be prepared in a low dew point environment such as -20°C or lower, -40°C or lower, or -60°C or lower. The recovery agent may be prepared by stirring a solvent, an aromatic hydrocarbon compound and a metal, in which case a stirrer or the like may be used. The solvent is dehydrated by distillation, immersion in molecular sieves, or the like, so that the water content is preferably 100 ppm or less before use.
以上説明した回復剤を、回復剤原液とも称する。回復剤原液において、溶質の濃度（還元状態の芳香族炭化水素化合物及び金属イオンの各々の濃度でもよい）は、０．０５ｍｏｌ／Ｌ以上１．１ｍｏｌ／Ｌ以下としてもよく、０．１ｍｏｌ／Ｌ以上１．１ｍｏｌ／Ｌ以下としてもよく、０．５ｍｏｌ／Ｌ以上１．０ｍｏｌ／Ｌ以下としてもよい。また、この濃度は、溶解度以下としてもよい。また、回復剤に含まれる還元状体の芳香族炭化水素化合物のモル数ＭA（ｍｏｌ）と金属イオンのモル数ＭB（ｍｏｌ）との比ＭA／ＭBは、１／１とすることが好ましいが、１．１／１．０～１．０／１．１としてもよいし、１．２／１．０～１．０／１．２としてもよい。 The recovery agent described above is also called a recovery agent undiluted solution. In the recovery agent undiluted solution, the concentration of the solute (which may be the concentration of each of the reduced aromatic hydrocarbon compound and the metal ion) may be 0.05 mol/L or more and 1.1 mol/L or less, or 0.1 mol/L. 1.1 mol/L or more, or 0.5 mol/L or more and 1.0 mol/L or less. Also, this concentration may be less than or equal to the solubility. Further, the ratio M A /M B of the number of moles M A (mol) of the reduced aromatic hydrocarbon compound contained in the recovery agent and the number of moles M B (mol) of the metal ion is set to 1/1. However, it may be 1.1/1.0 to 1.0/1.1 or 1.2/1.0 to 1.0/1.2.
電解液は、例えば、非水電解液二次電池の非水系電解液で例示した非水電解液としてもよく、非水系電解液で例示した有機溶媒と、非水系電解液で例示した支持塩と、を含むものとしてもよい。電解液の溶媒は、回復剤原液の溶媒と異なるものであればよいが、環状カーボネート、鎖状カーボネート、環状エステルのうちの１以上が好ましく、環状カーボネート及び鎖状カーボネートのうちの１以上がより好ましく、環状カーボネート及び鎖状カーボネートを含むことがさらに好ましい。電解液の溶媒は、エチレンカーボネート、ジメチルカーボネート、エチルメチルカーボネートのうちの１以上としてもよい。電解液の支持塩は、回復剤原液の溶質と異なるものであればよいが、ＬｉＰＦ6などの無機塩としてもよいし、ＬｉＦＳＩなどの有機塩としてもよい。電解液は、被膜形成剤や難燃剤等の添加剤を含んでもよい。電解液の組成は、回復対象の非水電解液二次電池の非水系電解液と同じでもよい。回復剤において、電解液の含有量は、例えば１０体積％以上９０体積％以下としてもよく、２０体積％以上８０体積％以下としてもよく、３０体積％以上７０体積％以下としてもよく、３０体積％以上６０体積％以下としてもよく、３０体積％以上５０体積％以下としてもよい。電解液を含む回復剤を調製する際には、回復剤原液と電解液とを混合すればよく、回復剤原液と電解液とを撹拌してもよく、スターラーなどを用いて撹拌してもよい。 The electrolyte may be, for example, the non-aqueous electrolyte exemplified in the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery, and the organic solvent exemplified in the non-aqueous electrolyte and the supporting salt exemplified in the non-aqueous electrolyte. , may be included. The solvent of the electrolytic solution may be different from the solvent of the recovery agent stock solution. More preferably, it contains a cyclic carbonate and a chain carbonate. The solvent of the electrolytic solution may be one or more of ethylene carbonate, dimethyl carbonate, and ethylmethyl carbonate. The supporting salt of the electrolytic solution may be different from the solute of the recovery agent stock solution, and may be an inorganic salt such as LiPF 6 or an organic salt such as LiFSI. The electrolyte may contain additives such as film-forming agents and flame retardants. The composition of the electrolyte may be the same as that of the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery to be recovered. In the recovery agent, the content of the electrolytic solution may be, for example, 10% by volume or more and 90% by volume or less, may be 20% by volume or more and 80% by volume or less, may be 30% by volume or more and 70% by volume or less, or may be 30% by volume. % or more and 60 volume % or less, or 30 volume % or more and 50 volume % or less. When preparing a recovery agent containing an electrolytic solution, the recovery agent stock solution and the electrolytic solution may be mixed, the recovery agent stock solution and the electrolytic solution may be stirred, or they may be stirred using a stirrer or the like. .
回復剤は、酸化還元電位が負極の酸化還元電位よりも高く正極の酸化還元電位よりも低いものとしてもよい。回復剤の酸化還元電位は、例えばＬｉ金属基準で０．５Ｖ以上２．５Ｖ以下としてもよいし、１．０Ｖ以上２．０Ｖ以下としてもよいし、１．２Ｖ以上１．９Ｖ以下としてもよい。 The recovery agent may have an oxidation-reduction potential higher than that of the negative electrode and lower than that of the positive electrode. The oxidation-reduction potential of the recovery agent may be, for example, 0.5 V or more and 2.5 V or less, 1.0 V or more and 2.0 V or less, or 1.2 V or more and 1.9 V or less based on Li metal. .
回復剤は、例えば、電子スピン共鳴（ＥＳＲ）法で測定したｇ値が１．９９６以上２．０２０以下の範囲に１本以上のシグナルが確認されるものとしてもよい。こうした回復剤では、還元状態の芳香族炭化水素化合物がラジカルの状態で存在していると考えられる。このｇ値は、ＥＳＲ測定で求めた共鳴周波数ν（Ｈｚ）及び磁場の強さＨ（ｍＴ）を用いて、ｈν＝ｇμBＨ（ただし、ｈはプランク定数（６．６２６１７６×１０-34Ｊｓ）、μBはボーア磁子（９．２７４０７８×１０-24ＪＴ-1））の式を用いて導出される。 For the recovery agent, for example, one or more signals can be confirmed in the g value range of 1.996 or more and 2.020 or less as measured by an electron spin resonance (ESR) method. In such a recovery agent, it is considered that the aromatic hydrocarbon compound in a reduced state exists in a radical state. This g value is obtained by using the resonance frequency ν (Hz) and the magnetic field strength H (mT) obtained by ESR measurement, hν = gμ B H (where h is Planck's constant (6.626176 × 10 -34 Js ), μ B is derived using the Bohr magneton (9.274078×10 −24 JT −1 )) equation.
［非水電解液二次電池の回復方法］
次に、非水電解液二次電池の回復方法について説明する。この非水電解液二次電池の回復方法は、非水電解液二次電池の容量を回復させる回復方法であって、上述した回復剤を用いて非水電解液二次電池の容量を回復させる回復工程、を含む。
[Recovery method for non-aqueous electrolyte secondary battery]
Next, a recovery method for the non-aqueous electrolyte secondary battery will be described. This non-aqueous electrolyte secondary battery recovery method is a recovery method for recovering the capacity of the non-aqueous electrolyte secondary battery, and recovers the capacity of the non-aqueous electrolyte secondary battery using the recovery agent described above. a recovery step;
（回復工程）
この工程では、非水電解液二次電池に対して、回復剤を注入して、非水電解液二次電池の容量を回復させる。回復対象となる非水電解液二次電池は、容量劣化した状態の電池（劣化電池とも称する）であり、例えば、非水電解液二次電池の定格容量に対して容量劣化した状態の電池としてもよい。回復対象となる非水電解液二次電池は、未使用品でも使用済み品でもよい。未使用品でも、長期保存などによって容量劣化することがある。
(Recovery process)
In this step, a recovery agent is injected into the non-aqueous electrolyte secondary battery to recover the capacity of the non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery to be recovered is a battery whose capacity has deteriorated (also referred to as a deteriorated battery). good too. A non-aqueous electrolyte secondary battery to be recovered may be an unused product or a used product. Even unused items may deteriorate in capacity due to long-term storage.
この工程では、回復剤を注入する際には、非水電解液二次電池を開封して回復剤を注入し開封部を塞いでもよいし、非水電解液二次電池に注射などで回復剤を注入し穿孔を塞いでもよい。回復剤を注入する際には、アルゴン雰囲気や窒素雰囲気などの不活性雰囲気下で注入してもよい。回復剤は、少なくとも正極と接触するように注入すればよいが、非水電解液と混合させてもよい。回復剤の注入量は、非水電解液二次電池の構成や、劣化度合いなどに応じて適宜定めることができる。回復剤の注入量は、例えば、非水電解液二次電池に含まれる非水電解液の体積［ｍＬ］に対して、１％以上１００％以下としてもよく、１０％以上７５％以下としてもよく、２５％以上５０％以下としてもよい。この工程では、回復剤を注入後、所定時間経過させることで、非水電解液二次電池の容量を回復させてもよい。その際、静置してもよいし、振とうしてもよいし、電圧を印加してもよい。この時間は、例えば、１時間以上４８時間以下としてもよく、６時間以上３６時間以下としてもよく、１２時間以上２４時間以下としてもよい。 In this step, when injecting the recovery agent, the non-aqueous electrolyte secondary battery may be opened and the recovery agent may be injected and the opening may be closed, or the recovery agent may be injected into the non-aqueous electrolyte secondary battery. may be injected to close the perforation. When injecting the recovery agent, the injection may be performed under an inert atmosphere such as an argon atmosphere or a nitrogen atmosphere. The recovery agent may be injected so as to contact at least the positive electrode, but may be mixed with the non-aqueous electrolyte. The injection amount of the recovery agent can be appropriately determined according to the configuration of the non-aqueous electrolyte secondary battery, the degree of deterioration, and the like. The injection amount of the recovery agent may be, for example, 1% or more and 100% or less, or 10% or more and 75% or less, with respect to the volume [mL] of the nonaqueous electrolyte contained in the nonaqueous electrolyte secondary battery. Well, it may be 25% or more and 50% or less. In this step, the capacity of the non-aqueous electrolyte secondary battery may be recovered by allowing a predetermined time to elapse after the recovery agent is injected. At that time, it may be left still, shaken, or a voltage may be applied. This time may be, for example, 1 hour or more and 48 hours or less, 6 hours or more and 36 hours or less, or 12 hours or more and 24 hours or less.
この工程で、回復剤を注入すると、例えば、図２に示すような回復反応が生じると考えられる。図２は、回復反応のスキームの一例を示す説明図であり、正極活物質がリチウム遷移金属複合酸化物である場合のスキームを示す説明図である。図２に示すように、回復剤では、芳香族炭化水素化合物のラジカルアニオン（図２ではＡｒｅ・-）と金属イオン（図２ではＬｉ+）とを有する溶質が、電子を供与する還元剤として機能するため、劣化した正極（図２ではＬｉn-yＭｅＯ2）に作用させることで、還元剤から正極へ電子と金属イオンが供与され、容量を回復させることができる。なお、電気的に中性の芳香族炭化水素化合物とリチウム原子との０価錯体は、金属リチウムのようにふるまうと考えられる。したがって、前述したリチウムの０価錯体が、劣化した正極に接触すると正極へ電子と金属イオンとを供給することによって電池活性を有する状態で正極の中に取り込まれるため、電池の容量を回復させることができると考えられる。金属イオンをＬｉＰＦ6などの塩の状態で劣化した正極に接触させても、このような容量回復の効果は得られない。 Injection of the recovery agent in this step is considered to cause a recovery reaction as shown in FIG. 2, for example. FIG. 2 is an explanatory diagram showing an example of a recovery reaction scheme, and an explanatory diagram showing the scheme when the positive electrode active material is a lithium-transition metal composite oxide. As shown in FIG. 2, in the recovery agent, a solute having a radical anion of an aromatic hydrocarbon compound (Are.- in FIG. 2) and a metal ion (Li + in FIG. 2) acts as a reducing agent that donates electrons. By acting on the deteriorated positive electrode (Li ny MeO 2 in FIG. 2), electrons and metal ions are donated from the reducing agent to the positive electrode, and the capacity can be recovered. A zero-valent complex of an electrically neutral aromatic hydrocarbon compound and a lithium atom is considered to behave like metallic lithium. Therefore, when the above-mentioned zero-valent complex of lithium comes into contact with the deteriorated positive electrode, it supplies electrons and metal ions to the positive electrode and is incorporated into the positive electrode in a state of having battery activity, so that the capacity of the battery can be recovered. is considered possible. Even if metal ions are brought into contact with the deteriorated positive electrode in the form of a salt such as LiPF 6 , such a capacity recovery effect cannot be obtained.
この工程では、上述の溶質と溶媒のほかに電解液を含む回復剤を用いるため、回復後の電池の容量がより向上する。この理由は以下のように推察される。例えば、電解液を含む回復剤では、電解液を含まない回復剤より、芳香族炭化水素化合物に対する溶媒和が大きく、芳香族炭化水素化合物のラジカルアニオンが電子や金属イオンを離しやすい。このため、電解液を含む回復剤を用いると、正極に溶質の電子や金属イオンが供給される際の活性化エネルギーが小さくなり、正極への金属イオンの供給が円滑に行われ、効率良く回復反応が進行して、回復後の電池の容量がより向上すると考えられる。また、電解液を含まない回復剤を非水電解液二次電池に注入した場合には非水電解液のイオン伝導度の低下や分極過電圧の上昇が懸念されるが、電解液を含む回復剤を用いることでイオン伝導度の低下や分極過電圧の上昇も抑制できると考えられる。こうして、非水電解液二次電池の容量が回復し、容量が回復した非水電解液二次電池（回復電池とも称する）が得られる。 In this step, a recovery agent containing an electrolytic solution in addition to the solute and solvent described above is used, so that the capacity of the battery after recovery is further improved. The reason for this is presumed as follows. For example, a recovery agent containing an electrolyte has a higher solvation with respect to an aromatic hydrocarbon compound than a recovery agent that does not contain an electrolyte, and the radical anion of the aromatic hydrocarbon compound easily separates electrons and metal ions. Therefore, when a recovery agent containing an electrolytic solution is used, the activation energy when solute electrons and metal ions are supplied to the positive electrode becomes small, and the metal ions are smoothly supplied to the positive electrode, resulting in efficient recovery. It is thought that the reaction progresses and the capacity of the battery after recovery is further improved. In addition, when a recovery agent containing no electrolyte is injected into a non-aqueous electrolyte secondary battery, there is concern that the ionic conductivity of the non-aqueous electrolyte will decrease and the polarization overvoltage will increase. It is considered that the decrease in ionic conductivity and the increase in polarization overvoltage can be suppressed by using . In this way, the capacity of the non-aqueous electrolyte secondary battery is recovered, and a non-aqueous electrolyte secondary battery (also referred to as a recovered battery) with recovered capacity is obtained.
以上詳述した回復剤及び非水電解液二次電池の回復方法では、非水電解液二次電池に回復剤を注入することで、非水電解液二次電池の容量を回復させることができる。この回復剤及び非水電解液二次電池の回復方法では、第三極を必要としない新規な回復方法を提供できる。また、この回復剤及び非水電解液二次電池の回復方法では、電解液を含む回復剤を用いることで、回復後の電池の容量をより向上させることができる。 In the recovery agent and the recovery method of the non-aqueous electrolyte secondary battery described in detail above, the capacity of the non-aqueous electrolyte secondary battery can be recovered by injecting the recovery agent into the non-aqueous electrolyte secondary battery. . This recovery agent and recovery method for a non-aqueous electrolyte secondary battery can provide a novel recovery method that does not require a third electrode. In addition, in this recovery agent and recovery method for a non-aqueous electrolyte secondary battery, the capacity of the battery after recovery can be further improved by using the recovery agent containing the electrolyte.
なお、本開示は上述した実施形態に何ら限定されることはなく、本開示の技術的範囲に属する限り種々の態様で実施し得ることはいうまでもない。 It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure.
例えば、上述した実施形態では、非水電解液二次電池の回復方法について説明したが、この非水電解液二次電池の回復方法では、容量劣化した非水電解液二次電池を用い、容量が回復した新たな非水電解二次電池を製造することができる。このため、非水電解液二次電池の回復方法は、非水電解液二次電池の製造方法であるともいえる。上述の非水電解液二次電池の回復方法を用いて非水電解液二次電池を製造してもよい。非水電解液二次電池の製造方法は、金属イオンをキャリアイオンとする容量劣化した非水電解液二次電池を準備する電池準備工程と、上述した非水電解液二次電池の回復方法で非水電解液二次電池の容量を回復させる回復工程と、を含むものとしてもよい。電池準備工程で準備する非水電解液二次電池は、上述した実施形態で説明した劣化電池と同様とすることができる。 For example, in the above-described embodiment, a method for recovering a non-aqueous electrolyte secondary battery has been described. It is possible to manufacture a new non-aqueous electrolytic secondary battery in which the is recovered. Therefore, the recovery method of the non-aqueous electrolyte secondary battery can also be said to be a manufacturing method of the non-aqueous electrolyte secondary battery. A non-aqueous electrolyte secondary battery may be manufactured using the recovery method for a non-aqueous electrolyte secondary battery described above. A method for manufacturing a non-aqueous electrolyte secondary battery includes a battery preparation step of preparing a non-aqueous electrolyte secondary battery with metal ions as carrier ions whose capacity has deteriorated, and the recovery method for the non-aqueous electrolyte secondary battery described above. and a recovery step of recovering the capacity of the non-aqueous electrolyte secondary battery. The non-aqueous electrolyte secondary battery prepared in the battery preparation step can be the same as the deteriorated battery described in the above embodiment.
以下には、本開示の非水電解液二次電池の回復方法でリチウムイオン電池の回復を行った例を実施例として説明する。なお、実験例２，４が実施例に相当し、実験例１，３が参考例に相当する。本開示は以下の実施例に何ら限定されることはなく、本開示の技術的範囲に属する限り種々の態様で実施し得ることはいうまでもない。 An example in which a lithium ion battery was recovered by the method for recovering a non-aqueous electrolyte secondary battery of the present disclosure will be described below as an example. Note that Experimental Examples 2 and 4 correspond to Examples, and Experimental Examples 1 and 3 correspond to Reference Examples. The present disclosure is by no means limited to the following examples, and it goes without saying that various aspects can be implemented as long as they fall within the technical scope of the present disclosure.
［実験例１］
（非水電解液二次電池（劣化前電池））
正極には、ＬｉＮｉ1/3Ｃｏ1/3Ｍｎ1/3Ｏ2（ＮＣＭ、戸田工業製）を９２ｗｔ％、アセチレンブラック（デンカ株式会社製）を５ｗｔ％、ポリフッ化ビニリデン（クレハ製）を３ｗｔ％の割合で含む正極合材を、目付量７ｍｇ／ｃｍ2となるようにアルミ集電箔の片面に形成したものを用いた。負極には、黒鉛（ＯＭＡＣ１．５ｓ、大阪ガスケミカル製）を９８ｗｔ％、カルボキシメチルセルロース（ダイセル製）を１ｗｔ％、スチレンブタジエンゴム（ＪＳＲ製）を１ｗｔ％の割合で含む負極合材を、目付量４ｍｇ／ｃｍ2となるように銅集電箔の片面に形成したものを用いた。電解液には、エチレンカーボネートを３０ｖｏｌ％、ジメチルカーボネートを４０ｖｏｌ％、エチルメチルカーボネートを３０ｖｏｌ％の割合で含む混合溶媒に、ＬｉＰＦ6を１．１Ｍの濃度となるように溶解させたものを用いた。正極と負極の間に、１ｍＬの電解液を含侵させたポリプロピレンセパレータを挟み、ラミネートセルを作製した。これを劣化前電池とした。セルの電極面積は正極、負極ともに１０ｃｍ2とした。劣化前電池の抵抗をデジタルマルチメータにて測定したところ、セル抵抗は１０Ωｃｍ2であった。この非水電解液二次電池において、電池構成に応じて定められる放電下限電圧は３．０Ｖであり充電上限電圧は４．１Ｖであった。
[Experimental example 1]
(Non-aqueous electrolyte secondary battery (battery before deterioration))
For the positive electrode, 92 wt % of LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM, manufactured by Toda Kogyo), 5 wt % of acetylene black (manufactured by Denka Co., Ltd.), and 3 wt % of polyvinylidene fluoride (manufactured by Kureha) were used. % of the positive electrode mixture was formed on one side of an aluminum current collector foil so as to have a basis weight of 7 mg/cm 2 . For the negative electrode, a negative electrode mixture containing 98 wt% graphite (OMAC 1.5s, manufactured by Osaka Gas Chemicals), 1 wt% carboxymethyl cellulose (manufactured by Daicel), and 1 wt% styrene-butadiene rubber (manufactured by JSR) was used. A copper current collecting foil formed on one side so as to have a concentration of 4 mg/cm 2 was used. The electrolytic solution used was a mixed solvent containing 30 vol% ethylene carbonate, 40 vol% dimethyl carbonate, and 30 vol% ethyl methyl carbonate, in which LiPF 6 was dissolved to a concentration of 1.1M. . A polypropylene separator impregnated with 1 mL of electrolytic solution was sandwiched between the positive electrode and the negative electrode to prepare a laminate cell. This was used as the battery before deterioration. The electrode area of the cell was 10 cm 2 for both the positive electrode and the negative electrode. When the resistance of the battery before deterioration was measured with a digital multimeter, the cell resistance was 10 Ωcm 2 . In this non-aqueous electrolyte secondary battery, the discharge lower limit voltage was 3.0V and the charge upper limit voltage was 4.1V, which were determined according to the battery configuration.
（劣化電池）
作製したラミネートセルにおいて、電圧範囲３．０Ｖから４．１Ｖでのセルの電気容量の５０％に相当する容量（ＳＯＣ＝５０％）まで充電を行うことで、正極からＬｉを引き抜いて、模擬的に容量を減少させた状態の正極を得た（劣化正極とも称する）。その後セルを解体し、劣化正極を取り出した。そして、正極として劣化正極を用いた以外は劣化前電池の作製と同様にして、ラミネートセルを作製した。これを劣化電池とした。劣化電池について、４．１Ｖまで０．９ｍＡにてＣＣ充電を行った後、３．０Ｖまで０．９ｍＡでＣＣ放電を行い、そのときの放電容量を測定した。
(degraded battery)
In the produced laminate cell, by charging to a capacity (SOC = 50%) corresponding to 50% of the electric capacity of the cell in a voltage range of 3.0 V to 4.1 V, Li is extracted from the positive electrode and simulated A positive electrode with a reduced capacity was obtained (also referred to as a deteriorated positive electrode). After that, the cell was disassembled and the deteriorated positive electrode was taken out. Then, a laminate cell was produced in the same manner as the production of the battery before deterioration, except that the deteriorated positive electrode was used as the positive electrode. This was defined as a deteriorated battery. The deteriorated battery was CC-charged to 4.1 V at 0.9 mA, then CC-discharged to 3.0 V at 0.9 mA, and the discharge capacity at that time was measured.
（回復剤）
不活性雰囲気下において、テトラヒドロフラン（ＴＨＦ）溶媒に対して１．０ｍｏｌ／Ｌになるようにナフタレンを溶解させ、その後、１．０ｍｏｌ／Ｌのリチウム金属を加えて撹拌し、上記式（７）に示す反応により、回復剤原液である濃緑色のラジカルアニオン液体組成物（リチウムナフタレニド＋ＴＨＦ）を調製し、これを回復剤とした。
(recovery agent)
Under an inert atmosphere, naphthalene is dissolved in a tetrahydrofuran (THF) solvent to a concentration of 1.0 mol/L, and then 1.0 mol/L of lithium metal is added and stirred to obtain the above formula (7). A dark green radical anion liquid composition (lithium naphthalenide + THF), which is a recovery agent stock solution, was prepared by the reaction shown and used as a recovery agent.
（劣化電池の回復）
劣化電池の一部をアルゴン雰囲気下で開封してピペットにて回復剤を０．５ｍＬ注入し、開封部を塞ぎ、そのまま２４時間放置した（回復処理）。こうして劣化電池の回復を行い、回復電池を得た。
(Recovery of deteriorated batteries)
A portion of the deteriorated battery was opened in an argon atmosphere, 0.5 mL of a recovery agent was injected with a pipette, and the opening was closed and left for 24 hours (recovery treatment). Thus, the deteriorated battery was recovered to obtain a recovered battery.
（回復電池の評価）
回復電池について、３．０Ｖから４．１Ｖの電圧範囲において、０．９ｍＡにてＣＣ充電を行った後、３．０Ｖまで０．９ｍＡでＣＣ放電を行い、そのときの放電容量を測定した。
(Evaluation of recovery battery)
The recovered battery was CC-charged at 0.9 mA in a voltage range from 3.0 V to 4.1 V, then CC-discharged at 0.9 mA to 3.0 V, and the discharge capacity at that time was measured.
［実験例２］
実験例２は、実験例１の回復剤（回復剤原液）と以下の電解液とを体積比で５：５となるように混合して調製した回復剤を用いた以外は、実験例１と同様とした。電解液は、エチレンカーボネートを３０ｖｏｌ％、ジメチルカーボネートを４０ｖｏｌ％、エチルメチルカーボネートを３０ｖｏｌ％の割合で含む混合溶媒に、ＬｉＦＳＩを１．１Ｍの濃度となるように溶解させて調製した。
[Experimental example 2]
Experimental Example 2 was the same as Experimental Example 1, except that a recovery agent prepared by mixing the recovery agent (recovery agent undiluted solution) of Experimental Example 1 and the following electrolytic solution at a volume ratio of 5:5 was used. Same. The electrolytic solution was prepared by dissolving LiFSI to a concentration of 1.1 M in a mixed solvent containing 30 vol % ethylene carbonate, 40 vol % dimethyl carbonate, and 30 vol % ethyl methyl carbonate.
［実験例３，４］
実験例３は、回復剤原液の溶媒をＴＨＦ溶媒からジメトキシエタン（ＤＭＥ）溶媒に変更した以外は、実験例１と同様とした。実験例４は、回復剤原液の溶媒をＴＨＦ溶媒からＤＭＥ溶媒に変更した以外は、実験例２と同様とした。
[Experimental examples 3 and 4]
Experimental Example 3 was the same as Experimental Example 1, except that the solvent of the recovery agent undiluted solution was changed from the THF solvent to the dimethoxyethane (DME) solvent. Experimental Example 4 was the same as Experimental Example 2, except that the solvent of the recovery agent undiluted solution was changed from the THF solvent to the DME solvent.
［ＥＳＲ測定］
ブルカー社製電子スピン共鳴装置、ＥＬＥＸＳＹＳ－Ｅ５００を用いて、各種試料について電子スピン共鳴（ＥＳＲ）測定を行った。測定は、試料５０μＬを石英製の水溶液測定用ＥＳＲセルにいれ、表１に示す条件で行った。試料としては、実験例２において回復剤注入直後に電池から抽出した電解液、実験例２において回復剤注入後５日放置後に電池から抽出した電解液、実験例１の回復剤、実験例２の回復剤、実験例４の回復剤、を用いた。なお、リチウムナフタレニドが電子スピン共鳴に対して活性を示すことは、例えば、J. Am. Chem. Soc. 1954, 76, 13, 3367-3369などで報告されている。
[ESR measurement]
Various samples were subjected to electron spin resonance (ESR) measurement using an electron spin resonance apparatus, ELEXSYS-E500 manufactured by Bruker. The measurement was performed under the conditions shown in Table 1 by putting 50 μL of the sample in a quartz ESR cell for measuring an aqueous solution. The samples used were the electrolyte solution extracted from the battery immediately after the recovery agent was injected in Experimental Example 2, the electrolyte solution extracted from the battery after standing for 5 days after the recovery agent was injected in Experimental Example 2, the recovery agent of Experimental Example 1, and the electrolytic solution of Experimental Example 2. The recovery agent, the recovery agent of Experimental Example 4, was used. It is reported, for example, in J. Am. Chem. Soc. 1954, 76, 13, 3367-3369 that lithium naphthalenide exhibits activity on electron spin resonance.
［実験結果］
実験例１～４の結果を表２にまとめた。また、実験例１～４について、容量回復前後の放電容量を図３のグラフにまとめた。表２及び図３に示すように、電解液を含む回復剤を用いた実験例２，４では、いずれも容量が回復することがわかった。また、回復剤原液の溶媒がＴＨＦである実験例１，２を比較すると、電解液を含む回復剤を用いた実験例２の方が回復容量が大きく、回復剤原液の溶媒がＤＭＥである実験例３，４を比較すると、電解液を含む回復剤を用いた実験例４の方が回復容量が大きかった。このことから、電解液を含む回復剤を用いると、回復後の電池の容量がより向上することがわかった。こうした効果が得られる理由等について、ＥＳＲ測定結果を用いて考察した。
[Experimental result]
The results of Experimental Examples 1 to 4 are summarized in Table 2. Further, the discharge capacities before and after the capacity recovery of Experimental Examples 1 to 4 are summarized in the graph of FIG. As shown in Table 2 and FIG. 3, in Experimental Examples 2 and 4 using the recovery agent containing the electrolytic solution, it was found that the capacity was recovered. Further, when comparing Experimental Examples 1 and 2 in which the solvent of the recovery agent undiluted solution is THF, Experimental Example 2 using the recovery agent containing the electrolytic solution has a larger recovery capacity, and the experiment in which the solvent of the recovery agent undiluted solution is DME. Comparing Examples 3 and 4, Experimental Example 4 using a recovery agent containing an electrolytic solution had a larger recovery capacity. From this, it was found that the use of the recovery agent containing the electrolytic solution further improved the capacity of the battery after recovery. The reason why such an effect can be obtained was considered using the ESR measurement results.
図４に、実験例２において回復剤注入直後に電池から抽出した電解液及び実験例２において回復剤注入後５日間放置後に電池から抽出した電解液のＥＳＲ測定結果を示した。図４に示すように、いずれの電解液にも、ナフタレニドアニオンラジカルと考えられるシグナルがｇ＝２．００１の位置に確認された。これは、リチウムナフタレニドでは、リチウムの最外殻電子である２ｓ１電子をナフタレニド配位子に渡してはいるが、ナフタレニド配位子側は単なるアニオンではなくアニオンラジカルになっていることを示していると推察された。 FIG. 4 shows the ESR measurement results of the electrolyte solution extracted from the battery immediately after injection of the recovery agent in Experimental Example 2 and the electrolyte solution extracted from the battery after standing for 5 days after the injection of the recovery agent in Experimental Example 2. As shown in FIG. As shown in FIG. 4, a signal considered to be a naphthalenide anion radical was confirmed at the position of g=2.001 in both electrolytic solutions. This indicates that in lithium naphthalenide, the 2s1 electron, which is the outermost electron of lithium, is transferred to the naphthalenide ligand, but the naphthalenide ligand side is not a mere anion but an anion radical. It was speculated that
図４に示すように、ナフタレニドアニオンラジカルと考えられるシグナルは、回復剤注入直後に比べて５日放置後の方が振幅（強度）が大きく減少した。これは、ナフタレニドアニオンラジカルの電子がリチウムの２ｓ１電子に転換され、そのリチウムが正極活物質に挿入された結果、ナフタレニドアニオンラジカルが減少したことを示していると推察された。 As shown in FIG. 4, the amplitude (intensity) of the signal, which is considered to be naphthalenide anion radical, decreased significantly after leaving for 5 days compared to immediately after injection of the recovery agent. It was speculated that this indicates that electrons of naphthalenide anion radicals were converted to 2s1 electrons of lithium, and that lithium was inserted into the positive electrode active material, resulting in a decrease in naphthalenide anion radicals.
図５に、実験例２，４の回復剤のＥＳＲ測定結果を示した。ＴＨＦ溶媒を用いた実験例２（図中（１））のシグナルは、ＤＭＥ溶媒を用いた実験例４（図中（２））のシグナルよりも振幅（強度）が大きかった。これは、ＤＭＥ溶媒を用いた実験例４の方がナフタレニドに対する溶媒和が大きいことを示すと推察された。 FIG. 5 shows the ESR measurement results of the recovery agents of Experimental Examples 2 and 4. The signal of Experimental Example 2 ((1) in the figure) using THF solvent had a larger amplitude (intensity) than the signal of Experimental Example 4 ((2) in the figure) using DME solvent. It was speculated that this indicates that Experimental Example 4 using DME solvent has a greater solvation of naphthalenide.
図６に、実験例１，２の回復剤のＥＳＲ測定結果を示した。ただし、実験例１の回復剤は、測定の都合上１０ｍｍｏｌ／Ｌの低溶質濃度に調整して用いた。実験例１のシグナルは実験例２のシグナルよりも振幅（強度）が大きく超微細構造が明確であった。これは、実験例２の回復剤では電解液を入れることで実験例１の回復剤よりもナフタレニドに対する溶媒和が大きくなったことを示すと推察された。ナフタレニドに対する溶媒和が大きいと、リチウムナフタレニドがリチウムイオンや電子を離しやすいため、正極にリチウムが補償される際の活性化エネルギーが小さくなると推察された。これにより、実験例２では、正極へのリチウムイオンの供給が円滑に行われ、効率良く回復が進行し、電解液を加えない実験例１よりも回復後の電池容量が向上したものと推察された。 FIG. 6 shows the ESR measurement results of the recovery agents of Experimental Examples 1 and 2. As shown in FIG. However, the recovery agent of Experimental Example 1 was adjusted to a low solute concentration of 10 mmol/L for convenience of measurement. The signal of Experimental Example 1 had a larger amplitude (intensity) than the signal of Experimental Example 2, and the ultrafine structure was clear. It was presumed that this indicates that the recovery agent of Experimental Example 2 had greater solvation with respect to naphthalenide than the recovery agent of Experimental Example 1 by adding the electrolytic solution. When the solvation to naphthalenide is large, lithium naphthalenide tends to release lithium ions and electrons. As a result, in Experimental Example 2, lithium ions were smoothly supplied to the positive electrode, recovery proceeded efficiently, and it is assumed that the battery capacity after recovery was improved as compared with Experimental Example 1 in which no electrolytic solution was added. rice field.
２０ 非水電解液二次電池、２１ 電池ケース、２２ 正極、２３ 負極、２４セパレータ、２５ ガスケット、２６ 封口板、２７ 非水電解液。 20 non-aqueous electrolyte secondary battery, 21 battery case, 22 positive electrode, 23 negative electrode, 24 separator, 25 gasket, 26 sealing plate, 27 non-aqueous electrolyte.
Claims (9)
還元状態の芳香族炭化水素化合物と金属イオンとを有する溶質と、前記溶質を溶解する溶媒と、電解液と、を含む、
回復剤。 A recovery agent for recovering the capacity of a non-aqueous electrolyte secondary battery using metal ions as carrier ions,
comprising a solute having an aromatic hydrocarbon compound in a reduced state and a metal ion, a solvent that dissolves the solute, and an electrolytic solution;
recovery agent.
請求項１に記載の回復剤。
The restorative agent according to claim 1.
請求項１又は２に記載の回復剤。 the solute has metal ions of the same type as the carrier ions;
The restorative agent according to claim 1 or 2.
請求項１～３のいずれか１項に記載の回復剤。 including one or more of tetrahydrofuran and dimethoxyethane as the solvent;
The recovery agent according to any one of claims 1 to 3.
請求項１～４のいずれか１項に記載の回復剤。 Containing a cyclic carbonate and a chain carbonate as the electrolytic solution,
The restorative agent according to any one of claims 1 to 4.
請求項１～５のいずれか１項に記載の回復剤。 The electrolyte contains the same type of electrolyte as the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery,
The restorative agent according to any one of claims 1 to 5.
請求項１～６のいずれか１項に記載の回復剤。 Containing the electrolytic solution in a range of 10% by volume or more and 90% by volume or less,
The recovery agent according to any one of claims 1-6.
前記非水電解液二次電池に対して、請求項１～７のいずれか１項に記載の回復剤を注入して、前記非水電解液二次電池の容量を回復させる回復工程、
を含む、
非水電解液二次電池の回復方法。 A recovery method for recovering the capacity of a non-aqueous electrolyte secondary battery using metal ions as carrier ions,
A recovery step of injecting the recovery agent according to any one of claims 1 to 7 into the non-aqueous electrolyte secondary battery to recover the capacity of the non-aqueous electrolyte secondary battery,
including,
A recovery method for a non-aqueous electrolyte secondary battery.
請求項８に記載の非水電解液二次電池の回復方法で前記非水電解液二次電池の容量を回復させる回復工程と、
を含む、非水電解液二次電池の製造方法。 A battery preparation step of preparing a non-aqueous electrolyte secondary battery with metal ions as carrier ions and having deteriorated capacity;
A recovery step of recovering the capacity of the non-aqueous electrolyte secondary battery by the recovery method for the non-aqueous electrolyte secondary battery according to claim 8;
A method for manufacturing a non-aqueous electrolyte secondary battery, comprising:
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