JP2004511407A - Vanadium oxide hydrate composition - Google Patents

Abstract

Disclosed herein are novel vanadium oxide hydrate compositions that are highly suitable for use as electrode active materials in primary and secondary lithium and lithium ion batteries, and methods for their preparation.

Description

【００４３】
実施例
次の実施例１〜１６においては、酸化バナジウム水和物を、形成し、次いで当該技術では公知の他の物質と組合わせて、リチウム電池中に組込まれる電極を形成した。すべてのこれらの工程は、以下に示す方法にしたがって達成された。このように形成されたコイン電池のリチウム放電容量を、測定した。結果を、図１に示されるように、本発明のＶ_２Ｏ_５・ｎＨ_２Ｏを形成する際に用いられる酸バナジウム比に対してプロットした。
【００４４】
実施例１
ＬｉＶＯ_３　１８．２ｇを、１リットルのＰｙｒｅｘビーカー中で、テフロン被覆磁気撹拌バーで撹拌しながら、脱イオンＨ_２Ｏ　約４５０ｍｌに添加した。ビーカーの内容物を、沸点に加熱して、溶液を形成した。撹拌しながら、濃ＨＮＯ_３　７．５ｍｌを沸騰溶液に添加した。得られた溶液を、撹拌しながら、５分間沸騰し続けた。Ｈ／Ｖ比は０．７であった。
【００４５】
次いで、ビーカーを熱源から外し、撹拌を室温で３．５時間続けた。未洗浄のゲル状沈殿物を、吸引ろ過によってフィルター紙上に集めた。生成物を、十分に緩やかにろ過した。ろ過液はオレンジ色であった。これは、相当量の未沈殿バナジウムが存在することを示した。ろ過液は、多色ｐＨ紙片で測定して、約ｐＨ３であった。ろ過ケークを、ＩＲ加熱ランプ下で終夜乾燥し、物質　７．４ｇを得た。（Ｌｉ）_０．０７Ｖ_２Ｏ_５（ＮＯ_３）_０．０７・０．９Ｈ_２Ｏ　の組成を、化学および熱重量分析から得た。この組成に基づいて、生成物の収率　４２％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００４６】
粉砕して粉末が製造された後、粉末を、２００メッシュの篩いにかけて、カソードを製造するのに適した粉末が得られた。電極を製造するために、粉末　１．５０００ｇを、Ｓｕｐｅｒ　Ｐ　カーボンブラック（ＭＭＭ　Ｓ．Ａ．Ｃａｒｂｏｎ、Ｂｒｕｓｓｅｌｓ、Ｂｅｌｇｉｕｍから商業的に入手可能である）０．１３６４ｇ、およびシクロヘキサン中のＥＰＤＭゴムの４重量％溶液　１．７０５ｇと組合わせた。さらに、シクロヘキサン　２．５ｍｌを添加して流動性を向上した。混合物を、キャップ付きガラスバイアルに入れて、１５分間機械振盪器上で振盪して、カソードペーストを形成した。
【００４７】
カソードペーストを、Ｔｅｆｌｏｎ（登録商標）ＦＥＰ（Ｅ．Ｉ．ｄｕ　Ｐｏｎｔ　ｄｅ　Ｎｅｍｏｕｒｓ　ａｎｄ　Ｃｏｍｐａｎｙ、Ｗｉｌｍｉｎｇｔｏｎ　ＤＥ）のシート上に塗り、１５ミル間隙を有するドクターブレードを用いて引き伸ばして、フィルムを形成した。乾燥されたフィルム（粉末　８８重量％、バインダー　４重量％、およびカーボンブラック　８重量％からなる）を、Ｋａｐｔｏｎ（登録商標）ポリイミドシート（ＤｕＰｏｎｔ）の間に挿んで、２０００ｐｓｉおよび１１０℃でカレンダローラーを通してホットプレスして、リチウム電池のカソードとして用いるのに適した強化電極シート（ｃｏｎｓｏｌｉｄａｔｅｄ　ｅｌｅｃｔｒｏｄｅ　ｓｈｅｅｔ）を形成した。シートの厚さは、１１５マイクロメートルであった。
【００４８】
得られた強化電極シートを、電気化学的電池のＬｉ金属アノードに対するカソードとして用いた。ＥＣ／ＤＭＣ（炭酸エチレン／炭酸ジメチル）中のＬｉＰＦ_６が、電解質溶液としての役割を果たした。ガラス繊維セパレーターを、電極の間に用いた。カソード、アノードおよびセパレーターの円盤を、パンチで切断した。乾燥窒素雰囲気において、カソードおよびセパレーター片を電解質溶液に浸漬し、次いでＬｉと共にコイン電池のパンに積重ね、２３２５　Ｃｏｉｎ　Ｃｅｌｌ　Ｃｒｉｍｐｅｒ　Ｓｙｓｔｅｍ（Ｎａｔｉｏｎａｌ　Ｒｅｓｅａｒｃｈ　Ｃｏｕｎｃｉｌ　ｏｆ　Ｃａｎａｄａによって製造される）を用いて、圧力下でシーリングした。コイン電池を、上記のように試験した。初期放電容量は、３１５ｍＡｈ／ｇであることが測定された。
【００４９】
実施例２
無水Ｖ_２Ｏ_５　１５．６ｇおよびＬｉＯＨ・Ｈ_２Ｏ　７．２ｇを、脱イオン水　９００ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、希Ｈ_２ＳＯ_４（濃Ｈ_２ＳＯ_４　３．６ｍｌをＨ_２Ｏ　４０ｍｌと組合わせて製造された）を、沸騰溶液に添加し、酸添加後の加熱時間は３５分であった。Ｈ／Ｖ比は０．７５であった。
【００５０】
次いで、ビーカーを熱源から外し、撹拌を停止した。未洗浄のゲル状固形物（１時間後に沈積しなかった）を、吸引ろ過によってフィルター紙上に集めた。生成物を、十分に緩やかにろ過した。ろ過液はオレンジ色であった。これは、相当量の未沈殿バナジウムが存在することを示した。ろ過液は、多色ｐＨ紙片で測定して、約ｐＨ３であった。ろ過ケークを、大きなカバーグラス上に塗り、室温で４日間およびＩＲ加熱ランプ下で２時間乾燥し、乾燥粉末　１２．５ｇを得た。不純物層（Ｌｉ_２ＳＯ_４・Ｈ_２Ｏと考えられる）を、Ｘ−線粉末回折で認めた。非反応性不純物は、活物質を希釈し、全Ｌｉ挿入容量を低減する効果を有する。生成物の収率　６５％が予測された。
【００５１】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１０８マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、２６５ｍＡｈ／ｇであることが見出された。
【００５２】
実施例３
ＬｉＶＯ_３　１８．２ｇを、脱イオン水　９００ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、希Ｈ_２ＳＯ_４（濃Ｈ_２ＳＯ_４　４．８ｍｌをＨ_２Ｏ　２０ｍｌと組合わせて製造された）を、沸騰溶液に添加し、酸添加後の加熱時間は１５分であった。Ｈ／Ｖ比は１．０であった。
【００５３】
次いで、ビーカーを熱源から外し、撹拌を停止した。固形物を、ビーカーが触れられる程度の冷たさになるまで沈積させた。上澄み液　約４００ｍｌをデカントした。デカントされた上澄み液は、淡い黄色であった。これは、若干の未沈殿バナジウムが存在することを示した。
【００５４】
新しい水　約４００ｍｌを、ビーカーの沈殿物に添加した。次いで、これを約１分間撹拌して水とスラリー化した。沈殿物を、１０分間沈積させ、上澄み液　約５００ｍｌをデカントした。新しいＨ_２Ｏ　約５００ｍｌを添加し、１分間スラリー化した。沈殿物を、約２０分間沈積させ、再度上澄み液をデカントした。
【００５５】
固形物を、吸引ろ過によってフィルター紙上に集めた。ろ過液は、多色ｐＨ紙片で測定して、約ｐＨ３であった。ろ過ケークを、大きなカバーグラス上に塗り、ＩＲ加熱ランプ下で乾燥し、乾燥粉末　１７．２ｇを得た。（Ｌｉ）_０．１４Ｖ_２Ｏ_５（ＳＯ_４）_０．０７１．１Ｈ_２Ｏ　の組成を、化学および熱重量分析から得た。この組成に基づいて、生成物の収率　９７％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００５６】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１１５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３５５ｍＡｈ／ｇであることが見出された。
【００５７】
実施例４
無水Ｖ_２Ｏ_５　５０．０ｇおよびＬｉＯＨ・Ｈ_２Ｏ　２３．１ｇを、６００ｍｌのＰｙｒｅｘビーカーにおいて、脱イオン水　３５０ｍｌと組合わせ、テフロン被覆磁気撹拌バーで撹拌し、約８０℃に加熱して、溶液を形成した。撹拌しながら、濃ＨＣｌ　５０ｍｌを高温溶液に添加した。Ｈ／Ｖ比は１．１であった。１５分後、加熱および撹拌を停止し、スラリーを室温に冷却した。
【００５８】
固形物を、吸引ろ過によってフィルター紙上に集めた。ろ過ケークを、ＩＲ加熱ランプ下で終夜乾燥し、次いで新しい脱イオン水　約５００ｍｌで再スラリー化し、再度吸引ろ過によってフィルター紙上に集め、ＩＲ加熱下で乾燥した。Ｌｉ_０．２Ｖ_２Ｏ_５Ｃｌ_０．２・０．５Ｈ_２Ｏ　の組成を、二段階反応
Ｌｉ_０．２Ｖ_２Ｏ_５Ｃｌ_０．２・０．５Ｈ_２Ｏ　→　Ｌｉ_０．２Ｖ_２Ｏ_５　＋　０．５Ｈ_２Ｏ　＋　０．１Ｃｌ_２
を仮定して、熱重量分析から得た。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００５９】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ９０マイクロメートルの電極を形成した。ただし、活物質、ＥＰＤＭバインダーおよびカーボンブラックの量は、それぞれ９０重量％、２重量％および８重量％であった。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３７８ｍＡｈ／ｇであることが見出された。
【００６０】
実施例５
ＮＨ_４ＶＯ_３　２０．１ｇを、脱イオン水　４５０ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、濃ＨＮＯ_３　１５ｍｌが沸騰溶液に添加され、酸添加後の加熱時間は５分であった。Ｈ／Ｖ比は１．４であった。
【００６１】
次いで、ビーカーを熱源から外し、撹拌を、ビーカーが触れられる程度の冷たさになるまで続けた。固形物を吸引ろ過によってフィルター紙上に集めた後、湿った固形物を、新しい脱イオン水　３５０ｍｌ中で、磁気撹拌バーで１分間撹拌してスラリー化し、次いで前述のように集めた。固形物を、再度、水の新しい３５０ｍｌ部分とスラリー化し、前述のように集めた。ろ過液は、ここで、約ｐＨ３であった。ろ過ケークを、空気中で１１０℃で乾燥した。生成物　１５．４ｇを得た。（ＮＨ_４）_０．１Ｖ_２Ｏ_５（ＮＯ_３）_０．１・０．８Ｈ_２Ｏ　の組成を、熱重量分析から得た。この組成に基づいて、生成物の収率　８８％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００６２】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１２５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３６７ｍＡｈ／ｇであることが見出された。
【００６３】
実施例６
ＬｉＶＯ_３　１８．２ｇを、脱イオン水　４５０ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、濃ＨＮＯ_３　１５ｍｌが沸騰溶液に注意深く添加され、酸添加後の加熱時間は１０分であった。Ｈ／Ｖ比は１．４であった。
【００６４】
次いで、ビーカーを熱源から外し、ほぼ室温に冷却させた。固形物を吸引ろ過によってフィルター紙上に集めた後、湿った固形物を、新しい脱イオン水　４００ｍｌ中で、磁気撹拌バーで１分間撹拌してスラリー化し、次いで前述のように集めた。ろ過液は、多色ｐＨ紙片で測定して、約ｐＨ１であった。ろ過ケークを、ＩＲ加熱ランプ下で乾燥して、乾燥生成物　１５．５ｇを得た。（Ｌｉ）_０．０５Ｖ_２Ｏ_５（ＮＯ_３）_０．０５・１Ｈ_２Ｏ　の組成を、化学および熱重量分析から得た。この組成に基づいて、生成物の収率　８９％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００６５】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１１０マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３４０ｍＡｈ／ｇであることが見出された。
【００６６】
実施例７
ＮＨ_４ＶＯ_３　２０．１ｇを、脱イオン水　９００ｍｌと組合わせ、実施例５におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、酸添加後の加熱時間は２０分であった。
【００６７】
次いで、ビーカーを熱源から外し、撹拌を停止した。固形物は、迅速に沈積し、５分間沈積させた。上澄み液　約６００ｍｌをデカントした。デカントされた上澄み液は、淡い黄色であった。これは、若干の未沈殿バナジウムが存在することを示した。新しいＨ_２Ｏ　約７００ｍｌを、ビーカーの沈殿物に添加し、次いで約１分間撹拌して水とスラリー化した。沈殿物を、１０分間沈積させ、上澄み液　約７００ｍｌをデカントした。新しいＨ_２Ｏ　約７００ｍｌを、添加し、１分間スラリー化した。沈殿物を、約２０分間沈積させ、再度上澄み液をデカントした。上澄み液は、約ｐＨ２であった。生成物は、容易かつ迅速に、吸引ろ過によってフィルター紙上に集められた。湿ったケークを、大きなカバーグラス上に粉砕し、空気中で室温で３．５日乾燥して、物質　１５．８ｇを得た。嵩だかの生成物は、容易に、乳鉢中で粉末化された。（ＮＨ_４）_０．１Ｖ_２Ｏ_５（ＮＯ_３）_０．１・０．７Ｈ_２Ｏ　の組成を、熱重量分析から得た。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。この組成に基づいて、生成物の収率　９１％が計算された。
【００６８】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１３０マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３７０ｍＡｈ／ｇであることが見出された。
【００６９】
実施例８
ＮＨ_４ＶＯ_３　８．２ｇを、脱イオン水　１５０ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、濃ＨＮＯ_３　６．６ｍｌが添加され、酸添加後の加熱時間は２分であった。Ｈ／Ｖ比は１．５であった。
【００７０】
次いで、ビーカーを熱源から外し、撹拌を、ビーカーが触れられる程度の暖かさになるまで続けた。生成物は、容易かつ迅速に、吸引ろ過によってフィルター紙上に集められた。未洗ケークを、終夜赤外線加熱ランプ下で乾燥した。
【００７１】
（ＮＨ_４）_０．１Ｖ_２Ｏ_５（ＮＯ_３）_０．１・１Ｈ_２Ｏ　の組成を、熱重量分析から得た。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００７２】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１２０マイクロメートルの電極を形成した。ただし、活物質、ＥＰＤＭバインダーおよびカーボンブラックの量は、それぞれ９０重量％、２重量％および８重量％であった。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３８３ｍＡｈ／ｇであることが見出された。
【００７３】
実施例９
ＭｇＶ_２Ｏ_６　１８．３ｇを、実施例３におけるように、Ｖ_２Ｏ_５・ｎＨ_２Ｏを製造するのに用いた。ただし、脱イオン水　２０ｍｌ中に濃Ｈ_２ＳＯ_４　９．５ｍｌの溶液が添加された。Ｈ／Ｖ比は２．１であった。
【００７４】
次いで、ビーカーを熱源から外し、撹拌を停止した。固形物は、迅速に沈積し、５分間沈積させた。上澄み液　約７００ｍｌをデカントした。デカントされた上澄み液は、淡い黄色であった。これは、若干の未沈殿バナジウムが存在することを示した。新しいＨ_２Ｏ　約７００ｍｌを、ビーカーの沈殿物に添加した。これは、次いで約１分間撹拌して水とスラリー化した。沈殿物を、１０分間沈積させ、上澄み液　約７００ｍｌをデカントした。洗浄／デカント工程を、さらに二回繰返した。最後の洗浄からの上澄み液は、ｐＨ３〜４であった。生成物は、容易かつ迅速に、吸引ろ過によってフィルター紙上に集められた。湿ったケークを、大きなカバーグラス上に粉砕し、空気中で室温で２．５日間および赤外線加熱ランプ下で５時間乾燥した。結果、１６．３ｇを得た。生成物は、容易に乳鉢中で粉末化された。生成物の収率　９６％が推測された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００７５】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１２３マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３６５ｍＡｈ／ｇであることが見出された。
【００７６】
実施例１０
ＮＨ_４ＶＯ_３　２０．１ｇを、脱イオン水　９００ｍｌと組合わせ、実施例１におけるように処理して、Ｖ_２Ｏ_５・ｎＨ_２Ｏを形成した。ただし、脱イオンＨ_２Ｏ　２５ｍｌ中に濃Ｈ_２ＳＯ_４　９．６ｍｌの溶液が用いられ、酸添加後の加熱時間は２０分であった。Ｈ／Ｖ比は２であった。
【００７７】
次いで、ビーカーを熱源から外し、撹拌を停止した。固形物は、迅速に沈積した。洗浄を、実施例７に示されるように行った。最終上澄み液は、約ｐＨ２であった。生成物は、容易かつ迅速に、吸引ろ過によってフィルター紙上に集められた。湿ったケークは、容易に、大きなカバーグラス上に粉砕され、典型的な方法で乾燥されて、生成物　１６．２ｇが得られた。嵩だかの物質は、容易に乳鉢中で粉末化された。（ＮＨ_４）_０．１２Ｖ_２Ｏ_５（ＳＯ_４）_０．０６・０．８Ｈ_２Ｏ　の組成を、化学および熱重量分析から得た。この組成に基づいて、生成物の収率　９２％が計算された。生成物は、３０，０００×までのＳＥＭイメージによって、非繊維状であることが示された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００７８】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１３０マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３７０ｍＡｈ／ｇであることが見出された。
【００７９】
実施例１１
実施例１０を、繰返した。ただし、脱イオンＨ_２Ｏ　４０ｍｌ中に濃Ｈ_２ＳＯ_４　９．６ｍｌの溶液が用いられ、酸添加後の加熱時間は６０分であった。Ｈ／Ｖ比は２であった。生成物　１５．４ｇが回収された。
【００８０】
（ＮＨ_４）_０．１２Ｖ_２Ｏ_５（ＳＯ_４）_０．０６・０．６Ｈ_２Ｏ　の組成を、熱重量分析から得た。この組成に基づいて、生成物の収率　８９％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００８１】
得次いで、られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１２５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３７４ｍＡｈ／ｇであることが見出された。
【００８２】
実施例１２
実施例７を、繰返した。ただし、濃ＨＮＯ_３　３０ｍｌが添加された。Ｈ／Ｖ比は２．８であった。実施例７におけるように洗浄し乾燥した後、物質　１２．４ｇを回収した。（ＮＨ_４）_０．０９Ｖ_２Ｏ_５（ＮＯ_３）_０．０９・０．５Ｈ_２Ｏ　の組成を、熱重量分析から得た。この組成に基づいて、生成物の収率　７３％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００８３】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１１５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３５０ｍＡｈ／ｇであることが見出された。
【００８４】
実施例１３
実施例１０を、繰返した。ただし、脱イオンＨ_２Ｏ　４０ｍｌ中に濃Ｈ_２ＳＯ_４　１９．２ｍｌの溶液が用いられた。Ｈ／Ｖ比は４であった。生成物　１３．６ｇが回収された。（ＮＨ_４）_０．１２Ｖ_２Ｏ_５（ＳＯ_４）_０．０６・１Ｈ_２Ｏ　の組成を、熱重量分析から得た。この組成に基づいて、生成物の収率　７６％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００８５】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１１５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３２５ｍＡｈ／ｇであることが見出された。
【００８６】
実施例１４
実施例３を、繰返した。ただし、脱イオンＨ_２Ｏ　５０ｍｌ中に濃Ｈ_２ＳＯ_４　１９．２ｍｌの溶液が用いられ、酸添加後の加熱時間は２０分であった。Ｈ／Ｖ比は４であった。洗浄および乾燥後、生成物　１０．８ｇが得られた。生成物の収率　６２％が推測された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００８７】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ９８マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３２１ｍＡｈ／ｇであることが見出された。
【００８８】
実施例１５
実施例１０を、繰返した。ただし、脱イオンＨ_２Ｏ　５０ｍｌ中に濃Ｈ_２ＳＯ_４　２８．８ｍｌの溶液が用いられた。Ｈ／Ｖ比は６であった。生成物　９．６ｇが回収された。生成物の収率　５５％が推測された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００８９】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１０５マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、２７２ｍＡｈ／ｇであることが見出された。
【００９０】
実施例１６
ＮＨ_４ＶＯ_３　２０．１ｇを、１リットルのＰｙｒｅｘビーカー中で、テフロン被覆磁気撹拌バーで撹拌しながら、脱イオンＨ_２Ｏ　約９００ｍｌに添加した。ビーカーの内容物を、沸点に加熱して、溶液を形成した。Ｓｕｐｅｒ　Ｐ　カーボンブラック（ＭＭＭ　Ｓ．Ａ．Ｃａｒｂｏｎ、Ｂｒｕｓｓｅｌｓ、Ｂｅｌｇｉｕｍから市販されている）１．５６ｇを、脱イオンＨ_２Ｏ　１００ｍｌ中で、振盪してスラリー化した。得られたスラリーを、沸騰溶液中に撹拌した。添加されたカーボンブラックの量は、生成物において、炭素の〜８重量％を示すであろう。
【００９１】
撹拌しながら、バナジウム−溶液／カーボン−ブラック混合物を、沸点に再加熱した。
【００９２】
濃Ｈ_２ＳＯ_４　９．６ｍｌを、脱イオンＨ_２Ｏ　３０〜４０ｍｌ中に希釈し、希釈された酸を、撹拌しながら沸騰組成物に添加した。Ｈ／Ｖ比は２であった。得られた混合物を、１５分間撹拌しながら沸騰し続けた。
【００９３】
次いで、ビーカーを熱源から外し、１時間撹拌した。固形物を、５分間沈積させた。暖かい上澄み液をデカントした。
【００９４】
沈殿物を、Ｈ_２Ｏの新しい一定分量中で、約１分間再スラリー化した。沈殿物を、再度、約１０分間沈積させ、上澄み液をデカントした。新しい水の、先と等分量である第二の分量を添加し、洗浄および固形物の分離工程を繰返した。
【００９５】
洗浄され、沈積された沈殿物を、吸引ろ過によってフィルター紙上に集めた。ろ過ケークを、小片に切り刻み、空気中で約６４時間乾燥し、続いてＩＲ加熱ランプ下で４時間乾燥した。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【００９６】
粉砕して粉末を製造された後、粉末を、２００メッシュの篩いにかけて、カソードを製造するのに適した粉末が得られた。生成物は、ＳＥＭによって、３０，０００倍の倍率まで非繊維状であることが見出された。
【００９７】
二つの電極を、異なるバインダーを用いて製造した。一つの電極は、実施例１に示されるように製造されて、厚さ１２０マイクロメートルの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。初期放電容量は、３５０ｍＡｈ／ｇであることが見出された。
【００９８】
他の電極については、粉末　１．００００ｇを、ＭＭＭ　Ｓｕｐｅｒ　Ｐ　カーボンブラック　０．１０００ｇ、Ｅｌｆ　Ａｔｏｃｈｅｍ製造のＫｙｎａｒｆｌｅｘ　０．１５３９ｇ、フタル酸ジブチル　０．２８５ｇ、およびアセトン　４．６ｍｌと組合わせた。混合物を、キャップ付きガラスバイアルに入れて、１５分間機械振盪器上で振盪した。
【００９９】
カソードペーストを、Ｔｅｆｌｏｎ（登録商標）ＦＥＰのシート上に塗り、１０ミル間隙を有するドクターブレードを用いて引き伸ばして、フィルムを形成した。アセトンを蒸発させた後、フタル酸ジブチルを、ジメチルエーテルを用いて抽出した。乾燥されたフィルム（活粉末　７９．８重量％、バインダー　１２．２重量％、およびカーボンブラック　８重量％からなる）を、Ｋａｐｔｏｎ（登録商標）シートの間に挿んで、２０００ｐｓｉおよび１１０℃でカレンダロールを通してホットプレスして、リチウム電池のカソードとして用いるのに適した強化電極シートを形成した。シートの厚さは、８６マイクロメートルであった。
【０１００】
カソードシートの円盤を、パンチで切断し、実施例１に示されるようにコイン電池中に組込まれた。初期放電容量は、３５７ｍＡｈ／ｇであることが見出された。
【０１０１】
実施例１７
実施例１６の電極を、Ｌｉ−イオン電気化学的電池のカソードとして用いた。アノードは、リチオ化グラファイトからなった。これは、室温で、Ｌｉ金属およびグラファイトの薄い円盤を反応させることによって、コイン電池を形成した。
【０１０２】
グラファイト粉末　ＭＣＭＢ２５−２８（Ｏｓａｋａ　Ｇａｓ　Ｃｏｍｐａｎｙ、Ｊａｐａｎ）　６．００００ｇを、Ｓｕｐｅｒ　Ｐ　カーボンブラック（ＭＭＭ　Ｓ．Ａ．Ｃａｒｂｏｎ、Ｂｒｕｓｓｅｌｓ、Ｂｅｌｇｉｕｍ）　０．１９３６ｇ、およびシクロヘキサン中のＥＰＤＭゴムの４重量％溶液　６．４５２ｇと組合わせた。さらに、シクロヘキサン　２．０ｍｌを、添加して流動性が向上された。混合物を、キャップ付きガラスバイアルに入れて、１５分間機械振盪器上で振盪して、グラファイトペーストを形成した。
【０１０３】
グラファイトペーストを、Ｔｅｆｌｏｎ（登録商標）ＦＥＰ（ＤｕＰｏｎｔ　Ｃｏｍｐａｎｙ、Ｗｉｌｍｉｎｇｔｏｎ、ＤＥ）のシート上に塗り、４０ミル間隙を有するドクターブレードを用いて引き伸ばして、フィルムを形成した。乾燥後、フィルム（グラファイト　９３重量％、バインダー　４重量％、およびカーボンブラック　３重量％からなる）を、Ｋａｐｔｏｎ（登録商標）ポリイミドシート（ＤｕＰｏｎｔ）の間に挿んで、２０００ｐｓｉおよび１１０℃でカレンダで通してホットプレスして、強化電極シートを形成した。シートの厚さは、約２９５マイクロメートルであった。
【０１０４】
カソード、グラファイト、Ｌｉ金属、および繊維ガラスセパレーターの円盤を、パンチで切断した。グラファイトおよびＬｉ金属は、乾燥窒素環境のグローブボックス内に置いた。グローブボックス内で、カソードおよびセパレーター片を、ＥＣ／ＤＭＣ（炭酸エチレン／炭酸ジメチル）内のＬｉＰＦ_６からなる電解質溶液中に浸漬し、次いで二つのグラファイト円盤および一つのＬｉ円盤（Ｌｉ円盤は約１００マイクロメートルの厚さを有する）に沿って、コイン電池のパンに積重ね、２３２５　Ｃｏｉｎ　Ｃｅｌｌ　Ｃｒｉｍｐｅｒ　Ｓｙｓｔｅｍ（Ｎａｔｉｏｎａｌ　Ｒｅｓｅａｒｃｈ　Ｃｏｕｎｃｉｌ　ｏｆ　Ｃａｎａｄａ製造）を用いて、圧力下でシーリングした。
【０１０５】
コイン電池を、試験前に９０時間そのままにした。グラファイトおよびＬｉ金属の量は、ほぼＬｉＣ_１０と同じＬｉ−グラファイト組成を示した。これは、Ｌｉ金属が、試験の前にコイン電池内に全く残留しないであろうことを示すと考えられた。コイン電池は、本明細書に用いられる標準的な方法にしたがって、試験された。ただし、電圧範囲は、リチウム−グラファイトアノードの電圧が、Ｌｉ金属に対して約０．０９ボルトであると観察されることから、１．５〜４．０ボルトないし１．４〜３．９ボルトに調整された。上記の非最適化コイン電池組立物においては、実施例１６で得られた初期放電容量の９２％は、本実施例のＬｉ−イオン電池に対して得られた。
【０１０６】
実施例１８
実施例１０を、繰返した。しかし、加熱溶液は、酸が添加される前に室温に冷却された。
【０１０７】
１０分後、ほんの少量の固形物が形成された。より多くの固形物は、１時間後に観察された。さらにより多くの固形物は、一夜撹拌した後に形成された。上澄み液は、可溶性の未沈殿バナジウムを含むことが見出された。上澄み液をデカントし、固形物を、約１分間撹拌して、新しい脱イオン水とスラリー化した。沈殿物を、約１０分間沈積させた。上澄み液の洗浄液（ｗａｓｈ）は多色ｐＨ紙片で測定して、ｐＨ３であった。洗浄され、沈積された沈殿物を、吸引ろ過によってフィルター紙上に集めた。ろ過ケークを、小片に切り刻み、空気中で一夜乾燥した。結果、１４ｇが得られた。
【０１０８】
所望の生成物の形成は、Ｘ−線粉末回折によって確認された。（ＮＨ_４）_０．１４Ｖ_２Ｏ_５（ＳＯ_４）_０．０７・１．１Ｈ_２Ｏ　の組成を、熱重量分析から得た。この組成に基づいて、生成物の収率　７７％が計算された。Ｘ−線粉末回折パターンでは、Ｖ_２Ｏ_５・ｎＨ_２Ｏの線のみが示された。
【０１０９】
次いで、得られたＶ_２Ｏ_５・ｎＨ_２Ｏの乾燥粉末を処理し、実施例１に示されるように組合わせて、厚さ１２０ｕｍの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。Ｌｉ容量は、上記の方法にしたがって、３３０ｍＡｈ／ｇであることが見出された。
【０１１０】
実施例１９
ＮＨ_４ＶＯ_３　２０．１ｇを、１リットルのＰｙｒｅｘビーカー中で、テフロン（登録商標）被覆磁気撹拌バーで撹拌しながら、脱イオンＨ_２Ｏ　約９００ｍｌに添加した。ビーカーの内容物を、沸点に加熱して、溶液を形成した。続いて、溶液を室温に冷却した。撹拌しながら、濃Ｈ_２ＳＯ_４（Ｈ_２Ｏ　５０ｍｌで希釈された）　１９．２ｍｌを、溶液に添加した。酸プロトン対バナジウム比は４であった。４時間後、痕跡量の固形物のみが、形成された。
【０１１１】
実施例２０
実施例１０を、繰返した。ただし、溶液の温度は、酸が添加される前に４５℃に低減された。
【０１１２】
反応を約４５℃で一夜保持した。酸プロトン対バナジウム比は２であった。上澄み液は、若干の可溶性の未沈殿バナジウムを含むことが見出された。上澄み液をデカントし、固形物を、約１分間撹拌して新しい脱イオン水とスラリー化した。沈殿物を、約１０分間沈積させた。上澄み液は、多色ｐＨ紙片で測定して、ｐＨ２〜３であった。洗浄され、沈積された沈殿物を、吸引ろ過によってフィルター紙上に集めた。ろ過ケークを、少片に切り刻み、空気中で乾燥して、生成物　１５．８ｇが得られた。Ｘ−線粉末回折では、生成物が、主として、所望の物質に加えて若干の（ＮＨ_４）_２Ｖ_６Ｏ_１６からなることを示した。Ｖ_２Ｏ_５・Ｈ_２Ｏの収率の推定値は、１０％の（ＮＨ_４）_２Ｖ_６Ｏ_１６不純物を仮定して、７５〜８０％であった。
【０１１３】
次いで、得られた乾燥混合相粉末を処理し、実施例１に示されるように組合わせて、厚さ１２０ｕｍの電極を形成した。これは、実施例１におけるように、コイン電池中に組込まれた。リチウム容量は、上記の方法にしたがって、３２９ｍＡｈ／ｇであることが見出された。
【図面の簡単な説明】
【図１】実施例１〜１６において、Ｈ／Ｖ比の関数として決定された初期放電容量の説明図を表す。
【図２ａ】実施例１０の非繊維状生成物について、走査電子顕微鏡写真を倍率１０，０００で示す。
【図２ｂ】実施例１０の非繊維状生成物について、走査電子顕微鏡写真を倍率３０，０００で示す。
【図３ａ】実施例１６の非繊維状生成物について、走査電子顕微鏡写真を倍率１０，０００で示す。
【図３ｂ】実施例１６の非繊維状生成物について、走査電子顕微鏡写真を倍率３０，０００での示す。
【図４】初期放電曲線および最初の再充電曲線を示す。これは、実施例１０で測定されたミリアンペア−時／電極活物質ｇ：電圧を示す。
【図５】初期放電曲線および最初の再充電曲線を示す。これは、実施例１６で測定されたミリアンペア−時／電極活物質ｇ：電圧を示す。[0001]
Field of the invention
The present invention relates to a novel vanadium oxide hydrate composition which is very suitable for use as an electrode active material in primary and secondary lithium and lithium ion batteries, and a method for preparing the same.
[0002]
Background of the Invention
As has long been known in the art, vanadium oxide hydrate generally has the formula ΔV₂O₅・ NH₂O, but typically high lithium ion insertion capacity, low hysteresis in charge / discharge cycles, high power density, and low sensitivity to discharge rate (as required in practice with rechargeable or "secondary" lithium batteries) ) Were not shown.
[0003]
No. 5,674,642 to Le et al. Discloses a fibrous V having a sufficiently high lithium insertion capacity.₂O₅・ NH₂An O composition has been disclosed, which has in fact been selected as the electrode active material for lithium batteries. Similar fibers and ribbons formed according to the method of Le et al. Passerini et al., Electrochimica @ Acta (44, 1999, 2209-2217); Life. Chem. Mater. (Vol. 3, 1991, pp. 578-593).
[0004]
It is known that an electrode active material is combined with a binder resin and carbon black to form an electrode paste or ink for use in battery applications. Carbon black significantly improves the performance of the electrode material, thereby allowing its theoretical capacity during fast charge / discharge to be achieved at an even higher rate. Le et al., Op. @Cit. Disclose these compositions. However, a significant sacrifice in capacity and reversibility is still involved during fast charge / discharge. That is, the problem is exacerbated more rapidly.
[0005]
Further improvement of the capacity with respect to the theoretical limit at the time of high-speed charging / discharging can be achieved by using a carbon black / V₂O₅・ NH₂It would be realized by forming an electrode with an even higher ratio of O. However, these ratios have practical limitations. Increasing the amount of carbon black without concomitantly increasing the binder impairs the mechanical integrity of the resulting electrode layer. Increasing the binder would then dilute the amount of electrode active material and significantly reduce the energy density of the resulting battery.
[0006]
In addition, Le et al. (Op. @Cit.) Reported that V with a residue of 4-7% by weight of chemically bound carbon solvent.₂O₅・ NH₂A composition of O is disclosed. Thereby, the electrochemical potential of the battery is improved. However, only the capacity and reversibility properties of the parent composition are retained.
[0007]
According to Le et al., V₂O₅・ NH₂A gelling method for producing O is disclosed. This is complicated, time consuming and more expensive. By textbooks, namely Cotton and WilkinsonAdvanced Inorganic Chemistry(4th edition, J. Wiley & Sons, Inc., 1980, p. 711) includes adding a mineral acid to an aqueous vanadate solution to form a red brick colored V-form.₂O₅Is disclosed. This method is also used in EP # 747123A2. However, the resulting products are disclosed as having low yields, being significantly contaminated, and having indeterminate properties. An analogous method is also used by Theobald, Bulletin de la la Societye Chimique de de France (1975, Nos. 7-8, 1607-1612). This also has poor results.
[0008]
Summary of the Invention
The present invention relates to M_xV₂O₅A_y・ NH₂O (where M is NH₄ ⁺, Na⁺, K⁺, Rb⁺, Cs⁺And Li⁺Selected from the group consisting of₃ ⁻, SO₄ ^-2And Cl⁻Selected from the group consisting of 0 <x <0.7, 0 <y <0.7, and 0.1 <n <2), wherein the method comprises:
Combining a water-soluble vanadate with water to form a solution, and adding a strong inorganic acid to the solution, wherein the acid proton / vanadium molar ratio ranges from 0.70: 1 to 6: 1. Steps that are within
M_xV₂O₅A_y・ NH₂A method for producing O is provided.
[0009]
In addition, the present invention relates to non-fibrous M_xV₂O₅A_y・ NH₂O (where M is NH₄ ⁺, Na⁺, K⁺, Rb⁺, Cs⁺And Li⁺Selected from the group consisting of₃ ⁻, SO₄ ^-2And Cl⁻An electrode active material composition selected from the group consisting of: 0 <x <0.7, 0 <y <0.7, and 0.1 <n <2). The material composition provides an electrode active material composition characterized by an initial discharge capacity of 315 to 400 mAh / g of the electrode active material composition g.
[0010]
Still further, there is provided an electrode composition comprising the electrode active material composition of the present invention.
[0011]
Finally, there is provided an electrochemical cell comprising the electrode composition comprising the electrode active material composition of the present invention.
[0012]
Detailed description
The present invention provides a highly purified non-fibrous form of V that is highly suitable for use as an electrode active material in batteries, particularly lithium and lithium ion primary and secondary batteries.₂O₅・ NH₂The present invention relates to a method of forming O, where 0.1 <n <2, and to compositions, electrodes, and electrochemical cells formed thereby. In carrying out the method of the present invention, the V₂O₅・ NH₂O is usually found to exhibit some contamination by residual cations of the vanadate and residual anions from the strong acids used in the process of the invention. This residue, for its intended use, has a V₂O₅・ NH₂It does not affect the suitability of O.
[0013]
Since the residue is chemically incorporated into the product, the product of the process of the invention has the formula M_xV₂O₅A_y・ NH₂More precisely indicated by O. Where M is NH₄ ⁺, Na⁺, K⁺, Rb⁺, Cs⁺And Li⁺Selected from the group consisting of:₃ ⁻, SO₄ ^-2And Cl⁻Selected from the group consisting of 0 <x <0.7, 0 <y <0.7, and 0.1 <n <2. Preferably, x and y are infinitely close to zero. However, in practice it is usually about 0.2.
[0014]
For purposes of clarity and ease of use in the present invention, the term "V₂O₅・ NH₂"O" is used as an abbreviation to indicate the product of the process of the present invention and will encompass the entire range of both x and y values (i.e., 0-0.7).
[0015]
In the method of the present invention, the water-soluble vanadate is dissolved in water, preferably with heating, followed by the desired V₂O₅・ NH₂The O product is precipitated in high yield. The resulting product exhibits a non-fibrous morphology and is characterized by a surprisingly high initial discharge capacity in test cells of standard lithium batteries with very high reversibility.
[0016]
For the purposes of the present invention, the term "initial discharge capacity" refers to the VD of the present invention.₂O₅・ NH₂Refers to the electrical discharge capacity of a standard lithium metal battery with the O composition incorporated as the electrode cathode active material. The “initial discharge capacity” measured in the standardized form is the value of V of the present invention.₂O₅・ NH₂It is believed to be a relative indicator of the intrinsic lithium ion insertion capacity of the O composition. For the purposes of the present invention, the initial discharge capacity is measured as follows. V of the present invention₂O₅・ NH₂O is combined with carbon black and a binder resin to form an electrode ink or paste, as in the various embodiments described below. The electrode ink or paste so formed is combined in the form of a standard lithium metal coin cell as shown below. The coin battery so formed is in a charged state. The battery is then subjected to a discharge in the range of 4-1.5 volts, with the voltage (V) and current (I) measured as a function of time. The measurement of the initial discharge capacity starts with a constant current discharge at 0.5 ma. When the voltage reaches 1.5 volts, the discharge mode changes to a constant voltage and the voltage is kept constant. Meanwhile, the current gradually decreases to 1/10 of the original value (that is, 0.05 ma). This constant voltage portion of the discharge (the cell is nearly equilibrium) reduces the potential drop due to current, so that the polarization of the remaining cell is primarily due to the overpotential required for lithium insertion into the cathode material. Has an effect. The initial discharge capacity is the total charge transfer at both the constant current and constant voltage due to the discharge. To make these measurements, it is appropriate to use a Maccor series 4000 tester (Maccor, Inc., Tulsa, Oklahoma) using a channel with a maximum current capacity of 10 ma and Version 3.0 (SP1) software. Was found.
[0017]
In the method of the present invention, water, preferably deionized water, is combined with the vanadate. The mixture so formed is preferably heated to a temperature in the range of 80 ° C. or higher, preferably with stirring. This includes the boiling point of the mixture to form a solution having a vanadium concentration in the range of 0.01 to 3M, preferably 0.1 to 1M. Suitable vanadates include ammonium, alkali and alkaline earth vanadates (NH₄VO₃, LiVO₃, NaVO₃, KVO₃, RbVO₃, CsVO₃And MgV₂O₆Etc.) are included. Preferably, NH₄VO₃, LiVO₃, KVO₃, MgV₂O₆It is. Most preferably, NH₄VO₃, LiVO₃And MgV₂O₆It is. Separately, V₂O₅Is combined in stoichiometric amount with aqueous ammonium, alkali or alkaline earth hydroxide, and the corresponding vanadate solution will be formed in situ. Most preferably, the solution is heated to its boiling point.
[0018]
To the preferably heated, most preferably boiling (so formed) solution, a strong mineral acid is added to provide an acid proton to vanadium ratio (hereinafter, referred to as) in the range of about 0.70: 1 to 6: 1. , "H / V ratio"). Suitable acids for practicing the invention include H₂SO₄, HNO₃, HCl, or other strong acids (except phosphorus-containing acids that would form undesirable vanadium phosphate by-products). Further, NH₄And Rb, and possibly the vanadate of Na, K and Cs, the vanadium acid ratio is sufficiently high, typically at least 1: 1 and M₂V₆O₁₆Must be prevented or minimized. The acid is incorporated in a concentrated or diluted form, but for safety, the diluted form is preferred.
[0019]
After the acid addition, mixing will be continued for at least 1 minute, preferably with heating at a temperature of at least 80 ° C, most preferably at the boiling point. However, it may last for several hours. Usually, mixing for 5 to 60 minutes will be sufficient. V obtained₂O₅・ NH₂The O precipitate will be recovered by any suitable method. This includes sedimentation followed by decanting of the supernatant, filtration, centrifugation and the like. The precipitate is characterized by a non-fibrous form and a contamination level of less than about 15%, usually less than about 4%.
[0020]
Dissolution of the vanadate in water will most often be achieved at any suitable temperature, including room temperature. However, in practicing the present invention, it is found that the dissolution rate is very slow at room temperature, especially when heated to a temperature at or near the boiling point. At temperatures below the boiling point, dissolution is considerably enhanced by stirring.
[0021]
V of the present invention by adding an acid to a sodium salt solution₂O₅・ NH₂O precipitation may be achieved at any suitable temperature, including room temperature. However, in practicing the present invention, it has been found that it is highly desirable to carry out the reaction at elevated temperatures, especially within the range of 80 ° C. to the boiling point of the solution. It is most preferred to carry out the reaction at the boiling point. In practicing the present invention, it is found that both low yields and low product quality or performance are likely to occur when the reaction temperature is below 80 ° C.
[0022]
Although not strictly necessary, the recovered solids, no matter how collected, are very likely to be reslurried with fresh water to remove contaminants followed by another solid recovery. preferable. The number of washing steps required to achieve the desired purity level will depend on the solubility of the impurities, the amount of water used, the desired purity level, and the efficiency of the slurrying step. In practicing the present invention, it has been found that, depending on many applications, it is sufficient to stop washing when the supernatant reaches about pH = 2 or higher.
[0023]
The recovered solid is then dried by any suitable means, including, but not limited to, radiant warming and oven heating. Following drying, milling and sieving, the V so produced₂O₅・ NH₂O is ready to be incorporated into the electrode composition.
[0024]
The resulting precipitate is a non-fibrous form of V with a high initial discharge capacity.₂O₅・ NH₂O. The ratio of precipitated dissolved vanadium (which mainly determines the single-pass product yield) is mainly determined by the H / V ratio. The highest yields are achieved with an H / V ratio of about 1: 1 to 2: 1. The term "non-fibrous" means having no microstructure of fibers or ribbons, as indicated by scanning electron microscopy at a magnification of about 30,000x. 2a and 2b show scanning electron micrographs of the sample of Example 10 herein at 10,000 and 30,000 magnifications, respectively. 3a and 3b show similar micrographs for the sample coated on carbon of Example 16 herein.
[0025]
Non-fibrous V produced by the method of the present invention₂O₅・ NH₂O is the amount of V produced by the acid precipitation step of the vanadium salt outside the H / V ratio limit of the process of the present invention.₂O₅・ NH₂It is characterized by a significantly higher initial discharge capacity than O. This is shown in FIG. In so doing, the initial discharge capacity is shown as a function of the H / V ratio for the particular embodiment illustrated below. Of particular note is that at the lower and upper limits of the H / V ratio range suitable for practicing the invention, the initial discharge capacity rapidly increases and decreases. Optimal H / V ratios are achieved with H / V ratios of about 1.5: 1 to 2.5: 1.
[0026]
Outside the preferred range of H / V ratio, the product begins to deteriorate, reducing yield, increasing contaminants and decreasing initial discharge capacity. Outside the range of 0.70-6 H / V, these desired properties are hardly obtained.
[0027]
V of the present invention₂O₅・ NH₂O confers a high degree of reversibility to the standard lithium test cells set forth herein. 99% of the available capacity will be recovered by recharging. It is shown schematically in FIGS. This indicates the discharge for Examples 10 and 16, respectively, shown below. In each case, a charge cycle representing the reversal of the discharge cycle follows. As can be seen, low polarization was observed. Examples 10 and 16 represent the same composite, with the difference that Example 16 includes the coated carbon composition and Example 10 does not. The polarization of the coated carbon sample indicates that the uncoated V on the carbon is low, as indicated by the very close curves in the low voltage region.₂O₅・ NH₂Less than that of the O sample. This beneficial effect of the coated carbon composition becomes even more pronounced as the rate of discharge and charge increases.
[0028]
Cycle life is defined as the number of charge and discharge cycles. The test coin cell will be marked before the discharge capacity is reduced to 80% of its initial value. It is believed by the inventors herein that the cycle life reaches an optimum value at an H / V ratio of about 4. In other words, it is assumed that there is some trade-off between yield and on the one hand initial discharge capacity and on the other hand cycle life.
[0029]
Further, in practicing the present invention, it is found that the initial discharge capacity is due to the cation of the vanadium salt used in the method of the present invention. The highest initial discharge capacity is V₂O₅・ NH₂O is NH₄VO₃, LiVO₃Or MgV₂O₆Achieved when manufactured from
[0030]
Those skilled in the art will appreciate that the V₂O₅・ NH₂It is understood that the requirements for any application of O involve different trade-offs for some of the process variables set forth herein, resulting in a product that is most suitable for that application. Will be.
[0031]
In one preferred embodiment of the method of the present invention, elemental carbon (eg, carbon black) is slurried in a vanadium salt solution prior to acid addition. In practicing the present invention, carbon black is added to the water before the vanadium salt is dissolved therein, at the same time as the vanadium salt is dissolved, or after the vanadium salt is dissolved. After the acid has been added in the manner indicated above, the resulting precipitated product is₂O₅・ NH₂It is a finely dispersed powder of carbon black coated with O. This is highly preferred for use with secondary or rechargeable lithium batteries. The coated carbon black product is V₂O₅・ NH₂It exhibits a high initial discharge capacity characteristic of O, with low polarization, high capacity retention at high discharge rates, and high vanadium utility or energy efficiency. The amount of carbon black found suitable for practicing the present invention depends on the final free carbon -V₂O₅・ NH₂The amount is in the range of 1 to 12% by weight, preferably 4 to 8% by weight of the total weight of the dry powder of O. 1-12% by weight corresponds to a carbon-vanadium molar ratio of about 0.1-1.2. In this case, n to 1.2 are preferable values.
[0032]
Any form of finely dispersed elemental carbon is suitable for practicing the present invention. Super P carbon black [MMM S. A. {Commercially available from Carbon (Brussels, Belgium)] is one of these suitable elemental carbons and is about 62 m²/ G surface area. For carbon blacks suitable for use in the present invention, higher surface areas are believed to be preferred over lower surface areas, although there is no particular limitation regarding surface area. In one embodiment, the carbon black is first slurried separately in an aqueous dispersion, and the resulting slurry is added to a heated vanadate solution.
[0033]
The method of the present invention will be performed in both batch and continuous modes. A continuous process using a recycle stream of unprecipitated vanadate is particularly desirable when the reaction is operated under relatively low yield conditions.
[0034]
In the method of the present invention, it is preferred that the values of x and y are reduced to near zero, and that any other residual ionic contaminants such as adsorbed protons are also removed. This is achieved by thoroughly washing the product precipitated in water, followed by filtration.
[0035]
In the art of electrochemical cell fabrication, the V₂O₅・ NH₂By combining an electrode active material such as O with carbon black and a binder resin, an electrode composition is formed to provide improved electronic conductivity, as well as excellent physical integrity, to the electrode composition. It is well known. However, in practice, 8% by weight of carbon black is found to represent a typical practical maximum carbon black concentration. Because amounts of more than 8% often have the undesirable consequence of making the electrode composition less workable and brittle. The present invention solves the problem of incorporating additional elemental carbon into the composition and minimizes the detrimental effect on the physical integrity of the electrode composition formed by its implementation. For example, preferred electrode compositions of the present invention include V₂O₅・ NH₂O-coated carbon black compositions are included. It incorporates 8% carbon black formed by the method of the present invention, as indicated above. The composition will be combined with an additional 8% of carbon black and a binder resin to form a tough, moldable electrode composition as taught in the art. It has improved electrochemical performance as expected from 16% carbon black and higher total carbon black concentration in the electrode composition.
[0036]
Suitable binder resins include EPDM rubber, polyvinylidene fluoride, and copolymers with, for example, hexafluoropropylene, as well as other resins known in the art that are suitable for this purpose. The binder resin is usually first dissolved in a temporary solvent before being combined with the other components of the electrode. Suitable solvents are well known in the art and include acetone, cyclohexane and cyclopentanone. Not all binders suitable for practicing the invention need be dissolved in the solvent.
[0037]
In practicing the present invention, V₂O₅・ NH₂The electrode composition of the present invention comprising elemental carbon coated with O₂O₅・ NH₂When O is not coated on elemental carbon,₂O₅・ NH₂It has been found that there are significant advantages over similar electrode compositions comprising O. These advantages include reduced polarization in the charge / discharge cycle, higher initial discharge capacity / g vanadium, and even lower initial discharge capacity with increasing discharge rate.
[0038]
V₂O₅・ NH₂The method of the present invention for producing O-coated carbon may also be used to add or dope other elements. For example, V₂O₅・ NH₂If a transition metal or metal compound is added before precipitating O, a chemically modified precipitation product is obtained after addition of the acid. This is the general formula M_XB_ZV₂O₅A_y・ NH₂It has O. Where M is V of the present invention.₂O₅・ NH₂A cation derived from the vanadate from which O was precipitated, and x = 0.0-0.7; A is an anion derived from the acid, and y = 0.0-0.7 And B is a transition (main group) or rare earth metal, and z = 0.0 to 1.0, and n = 0.1 to 2.0.
[0039]
The invention is further described in the following specific embodiments. Those skilled in the art will appreciate that the present invention is capable of numerous modifications, substitutions and rearrangements without departing from the spirit or essential characteristics of the invention.
[0040]
Most of the specific embodiments described below involve the formation of a standard electrochemical cell, wherein the electrode composition of the embodiment is used as a cathode to a lithium metal anode. Lithium-ion batteries are also formed by the method of the present invention and will be preferred in numerous applications.
[0041]
Lithium-ion batteries are assembled in a charged state, either by using an anode material that already contains a suitable cyclable lithium, or by some of its parts. This will be achieved in a manner known to those skilled in the art. For example, by contacting lithium metal or some other source of lithium with a carbon-based anode material in a battery assembly that would be able to accommodate the required cyclable lithium in a carbon structure. Other means for using the claimed materials in lithium-ion batteries include the intentional pre-lithiation step of vanadium oxide hydrate, for example, by either chemical or electrochemical means. There will be. This would increase the lithium content in the claimed materials to higher levels, which is desirable for use in lithium-ion batteries having an initial discharge anode. An example of a lithium ion battery is shown in Example 17.
[0042]
[Table 1]

[0043]
Example
In the following Examples 1-16, vanadium oxide hydrate was formed and then combined with other materials known in the art to form electrodes for incorporation into lithium batteries. All these steps were accomplished according to the methods set forth below. The lithium discharge capacity of the coin battery thus formed was measured. The results are shown in FIG.₂O₅・ NH₂Plotted against the vanadium acid ratio used in forming O.
[0044]
Example 1
LiVO₃18.2 g of deionized H in a 1 liter Pyrex beaker while stirring with a Teflon-coated magnetic stir bar₂O was added to about 450 ml. The contents of the beaker were heated to boiling to form a solution. While stirring, concentrated HNO₃$ 7.5 ml was added to the boiling solution. The resulting solution was kept boiling for 5 minutes with stirring. The H / V ratio was 0.7.
[0045]
The beaker was then removed from the heat and stirring was continued at room temperature for 3.5 hours. The unwashed gel precipitate was collected on filter paper by suction filtration. The product was filtered slowly enough. The filtrate was orange. This indicated that significant amounts of unprecipitated vanadium were present. The filtrate had a pH of about 3 as measured on a piece of multicolored pH paper. The filter cake was dried overnight under an IR heating lamp to give 7.4 g of material. (Li)_0.07V₂O₅(NO₃)_0.07・ 0.9H₂The composition of O was obtained from chemical and thermogravimetric analysis. Based on this composition, a product yield of 42% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0046]
After milling to produce a powder, the powder was sieved through a 200 mesh screen to obtain a powder suitable for producing a cathode. To make the electrode, 1.5000 g of powder, 0.1364 g of Super P carbon black (commercially available from MMM SA Carbon, Brussels, Belgium), and 4 weight of EPDM rubber in cyclohexane % Solution @ 1.705 g. Further, 2.5 mL of cyclohexane was added to improve the fluidity. The mixture was placed in a capped glass vial and shaken on a mechanical shaker for 15 minutes to form a cathode paste.
[0047]
The cathode paste was applied to a sheet of Teflon® FEP (EI du Pont de Nemours and Company, Wilmington DE) and stretched using a doctor blade with a 15 mil gap to form a film. The dried film (consisting of powder 88% by weight, binder 4% by weight, and carbon black 8% by weight) was inserted between Kapton® polyimide sheets (DuPont) and passed through a calendar roller at 2000 psi and 110 ° C. Hot pressing was performed to form a reinforced electrode sheet suitable for use as a cathode in a lithium battery. The thickness of the sheet was 115 micrometers.
[0048]
The resulting reinforced electrode sheet was used as a cathode for a Li metal anode of an electrochemical cell. LiPF in EC / DMC (ethylene carbonate / dimethyl carbonate)₆Served as an electrolyte solution. A glass fiber separator was used between the electrodes. The cathode, anode and separator disks were cut with a punch. In a dry nitrogen atmosphere, the cathode and separator pieces are immersed in an electrolyte solution, then stacked with Li in a coin cell pan and sealed under pressure using a 2325 Coin Cell Crimper System (manufactured by National Research Research Council of Canada). did. Coin cells were tested as described above. The initial discharge capacity was measured to be 315 mAh / g.
[0049]
Example 2
Anhydrous V₂O₅$ 15.6 g and LiOH.H₂O 7.2 g was combined with deionized water 900 ml and treated as in Example 1 to₂O₅・ NH₂O was formed. However, rare H₂SO₄(Dark H₂SO₄3.6 ml H₂(Prepared in combination with O @ 40 ml) was added to the boiling solution and the heating time after the acid addition was 35 minutes. The H / V ratio was 0.75.
[0050]
Then, the beaker was removed from the heat source and stirring was stopped. Unwashed gel-like solids (which did not settle after 1 hour) were collected on filter paper by suction filtration. The product was filtered slowly enough. The filtrate was orange. This indicated that significant amounts of unprecipitated vanadium were present. The filtrate had a pH of about 3 as measured on a piece of multicolored pH paper. The filter cake was spread on a large cover glass and dried at room temperature for 4 days and under an IR heating lamp for 2 hours to obtain 12.5 g of dry powder. Impurity layer (Li₂SO₄・ H₂O (probably O) was observed by X-ray powder diffraction. Non-reactive impurities have the effect of diluting the active material and reducing the total Li insertion capacity. A product yield of 65% was expected.
[0051]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 108 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 265 mAh / g.
[0052]
Example 3
LiVO₃18.2 g was combined with ｍｌ900 ml of deionized water and treated as in Example 1 to₂O₅・ NH₂O was formed. However, rare H₂SO₄(Dark H₂SO₄4.8 ml to H₂(Prepared in combination with O 20 ml) was added to the boiling solution and the heating time after the acid addition was 15 minutes. The H / V ratio was 1.0.
[0053]
Then, the beaker was removed from the heat source and stirring was stopped. The solid was allowed to settle until it was cold enough to touch the beaker. About 400 ml of the supernatant was decanted. The decanted supernatant was pale yellow. This indicated that some unprecipitated vanadium was present.
[0054]
About 400 ml of fresh water was added to the sediment of the beaker. This was then stirred for about 1 minute to slurry with water. The precipitate was allowed to settle for 10 minutes and about 500 ml of the supernatant was decanted. New H₂About 500 ml of O was added and slurried for 1 minute. The precipitate was allowed to settle for about 20 minutes, and the supernatant was again decanted.
[0055]
The solid was collected on filter paper by suction filtration. The filtrate had a pH of about 3 as measured on a piece of multicolored pH paper. The filter cake was spread on a large cover glass and dried under an IR heating lamp to give 17.2 g of dry powder. (Li)_0.14V₂O₅(SO₄)_0.071.1H₂The composition of O was obtained from chemical and thermogravimetric analysis. Based on this composition, a product yield of 97% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0056]
Then, the obtained V₂O₅・ NH₂The dry powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 115 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 355 mAh / g.
[0057]
Example 4
Anhydrous V₂O₅$ 50.0g and LiOH.H₂23.1 g of O was combined with 350 ml of deionized water in a 600 ml Pyrex beaker, stirred with a Teflon-coated magnetic stir bar, and heated to about 80 ° C. to form a solution. With stirring, 50 ml of concentrated HCl was added to the hot solution. The H / V ratio was 1.1. After 15 minutes, heating and stirring were stopped and the slurry was cooled to room temperature.
[0058]
The solid was collected on filter paper by suction filtration. The filter cake was dried under an IR heating lamp overnight, then reslurried with about 500 ml of fresh deionized water, collected again on filter paper by suction filtration and dried under IR heating. Li_0.2V₂O₅Cl_0.2・ 0.5H₂O composition, two-step reaction
Li_0.2V₂O₅Cl_0.2・ 0.5H₂O → Li_0.2V₂O₅+ 0.5H₂O + 0.1Cl₂
Was obtained from thermogravimetric analysis, assuming In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0059]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form a 90 micrometer thick electrode. However, the amounts of the active material, EPDM binder and carbon black were 90% by weight, 2% by weight and 8% by weight, respectively. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 378 mAh / g.
[0060]
Example 5
NH₄VO₃20.1 g was combined with 450 ml of deionized water and treated as in Example 1 to₂O₅・ NH₂O was formed. However, concentrated HNO₃15 ml was added to the boiling solution and the heating time after the acid addition was 5 minutes. The H / V ratio was 1.4.
[0061]
The beaker was then removed from the heat and stirring continued until the beaker was cold enough to touch. After collecting the solids on filter paper by suction filtration, the wet solids were slurried in 350 ml of fresh deionized water by stirring with a magnetic stir bar for 1 minute and then collected as described above. The solid was again slurried with a new 350 ml portion of water and collected as described above. The filtrate now had a pH of about 3. The filter cake was dried at 110 ° C. in air. 15.4 g of the product was obtained. (NH₄)_0.1V₂O₅(NO₃)_0.1・ 0.8H₂The composition of O was obtained from thermogravimetric analysis. Based on this composition, a product yield of 88% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0062]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 125 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 367 mAh / g.
[0063]
Example 6
LiVO₃18.2 g was combined with ｍｌ450 ml of deionized water and treated as in Example 1 to₂O₅・ NH₂O was formed. However, concentrated HNO₃15 ml was carefully added to the boiling solution and the heating time after the acid addition was 10 minutes. The H / V ratio was 1.4.
[0064]
The beaker was then removed from the heat and allowed to cool to about room temperature. After collecting the solids on filter paper by suction filtration, the wet solids were slurried in 400 ml of fresh deionized water by stirring with a magnetic stir bar for 1 minute and then collected as described above. The filtrate had a pH of about 1 as measured on a piece of multicolored pH paper. The filter cake was dried under an IR heating lamp to give 乾燥 15.5 g of dry product. (Li)_0.05V₂O₅(NO₃)_0.05・ 1H₂The composition of O was obtained from chemical and thermogravimetric analysis. Based on this composition, a product yield of 89% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0065]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form a 110 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 340 mAh / g.
[0066]
Example 7
NH₄VO₃20.1 g was combined with 900 ml of deionized water and treated as in Example 5 to₂O₅・ NH₂O was formed. However, the heating time after the addition of the acid was 20 minutes.
[0067]
Then, the beaker was removed from the heat source and stirring was stopped. The solids settled quickly and settled for 5 minutes. About 600 ml of the supernatant was decanted. The decanted supernatant was pale yellow. This indicated that some unprecipitated vanadium was present. New H₂About 700 ml of O was added to the beaker sediment and then stirred for about 1 minute to slurry with water. The precipitate was allowed to settle for 10 minutes and about 700 ml of the supernatant was decanted. New H₂About 700 ml of O was added and slurried for 1 minute. The precipitate was allowed to settle for about 20 minutes, and the supernatant was again decanted. The supernatant was about pH 2. The product was easily and quickly collected on filter paper by suction filtration. The wet cake was crushed on a large cover glass and dried in air at room temperature for 3.5 days to give 15.8 g of material. The bulky product was easily powdered in a mortar. (NH₄)_0.1V₂O₅(NO₃)_0.1・ 0.7H₂The composition of O was obtained from thermogravimetric analysis. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown. Based on this composition, a product yield of 91% was calculated.
[0068]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form a 130 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 370 mAh / g.
[0069]
Example 8
NH₄VO₃8.2 g, combined with 150 ml deionized water, treated as in Example 1,₂O₅・ NH₂O was formed. However, concentrated HNO₃$ 6.6 ml was added and the heating time after the acid addition was 2 minutes. The H / V ratio was 1.5.
[0070]
The beaker was then removed from the heat and stirring was continued until the beaker was warm enough to touch. The product was easily and quickly collected on filter paper by suction filtration. The unwashed cake was dried under an infrared heating lamp overnight.
[0071]
(NH₄)_0.1V₂O₅(NO₃)_0.1・ 1H₂The composition of O was obtained from thermogravimetric analysis. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0072]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 120 micrometers. However, the amounts of the active material, EPDM binder and carbon black were 90% by weight, 2% by weight and 8% by weight, respectively. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 383 mAh / g.
[0073]
Example 9
MgV₂O₆18.3 g of V as in Example 3₂O₅・ NH₂Used to produce O. However, concentrated H in 20 ml of deionized water₂SO₄9.5 ml of solution was added. The H / V ratio was 2.1.
[0074]
Then, the beaker was removed from the heat source and stirring was stopped. The solids settled quickly and settled for 5 minutes. About 700 ml of the supernatant was decanted. The decanted supernatant was pale yellow. This indicated that some unprecipitated vanadium was present. New H₂About 700 ml of O was added to the sediment of the beaker. This was then slurried with water with stirring for about 1 minute. The precipitate was allowed to settle for 10 minutes and about 700 ml of the supernatant was decanted. The washing / decanting step was repeated twice more. The supernatant from the last wash had a pH of 3-4. The product was easily and quickly collected on filter paper by suction filtration. The wet cake was ground on a large cover glass and dried in air at room temperature for 2.5 days and under an infrared heating lamp for 5 hours. As a result, 16.3 g was obtained. The product was easily powdered in a mortar. A product yield of 96% was estimated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0075]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form a 123 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 365 mAh / g.
[0076]
Example 10
NH₄VO₃20.1 g was combined with 900 ml of deionized water and treated as in Example 1 to₂O₅・ NH₂O was formed. However, deionized H₂O concentrated H in 25 ml₂SO₄9.6 ml of solution was used and the heating time after the acid addition was 20 minutes. The H / V ratio was 2.
[0077]
Then, the beaker was removed from the heat source and stirring was stopped. The solid settled out quickly. Washing was performed as described in Example 7. The final supernatant was about pH 2. The product was easily and quickly collected on filter paper by suction filtration. The wet cake was easily crushed on a large cover glass and dried in a typical manner to give 16.2 g of product. The bulky material was easily powdered in a mortar. (NH₄)_0.12V₂O₅(SO₄)_0.06・ 0.8H₂The composition of O was obtained from chemical and thermogravimetric analysis. Based on this composition, a product yield of 92% was calculated. The product was shown to be non-fibrous by SEM images up to 30,000 ×. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0078]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form a 130 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 370 mAh / g.
[0079]
Example 11
Example 10 was repeated. However, deionized H₂O concentrated H in 40ml₂SO₄9.6 ml of solution was used and the heating time after acid addition was 60 minutes. The H / V ratio was 2. 15.4 g of product was recovered.
[0080]
(NH₄)_0.12V₂O₅(SO₄)_0.06・ 0.6H₂The composition of O was obtained from thermogravimetric analysis. Based on this composition, a product yield of 89% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0081]
Then get V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 125 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 374 mAh / g.
[0082]
Example 12
Example 7 was repeated. However, concentrated HNO₃$ 30 ml was added. The H / V ratio was 2.8. After washing and drying as in Example 7, 12.4 g of material was recovered. (NH₄)_0.09V₂O₅(NO₃)_0.09・ 0.5H₂The composition of O was obtained from thermogravimetric analysis. Based on this composition, a product yield of 73% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0083]
Then, the obtained V₂O₅・ NH₂The dry powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 115 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 350 mAh / g.
[0084]
Example 13
Example 10 was repeated. However, deionized H₂O concentrated H in 40ml₂SO₄19.2 ml of solution was used. The H / V ratio was 4. 13.6 g of product was recovered. (NH₄)_0.12V₂O₅(SO₄)_0.06・ 1H₂The composition of O was obtained from thermogravimetric analysis. Based on this composition, a product yield of 76% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0085]
Then, the obtained V₂O₅・ NH₂The dry powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 115 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 325 mAh / g.
[0086]
Example 14
Example 3 was repeated. However, deionized H₂O concentrated H in 50ml₂SO₄19.2 ml of solution was used and the heating time after the acid addition was 20 minutes. The H / V ratio was 4. After washing and drying, 10.8 g of product was obtained. A product yield of 62% was estimated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0087]
Then, the obtained V₂O₅・ NH₂The dry powder of O was processed and combined as described in Example 1 to form a 98 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 321 mAh / g.
[0088]
Example 15
Example 10 was repeated. However, deionized H₂O concentrated H in 50ml₂SO₄28.8 ml of solution was used. The H / V ratio was 6. 9.6 g of product was recovered. A product yield of 55% was estimated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0089]
Then, the obtained V₂O₅・ NH₂The dried powder of O was processed and combined as described in Example 1 to form an electrode having a thickness of 105 micrometers. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 272 mAh / g.
[0090]
Example 16
NH₄VO₃20.1 g of deionized H in a 1 liter Pyrex beaker while stirring with a Teflon-coated magnetic stir bar.₂O was added to about 900 ml. The contents of the beaker were heated to boiling to form a solution. 1.56 g of Super @ P carbon black (commercially available from MMM @ SA Carbon, Brussels, Belgium) is deionized H₂Shake in O 100 ml to make a slurry. The resulting slurry was stirred into the boiling solution. The amount of carbon black added will represent ８8% by weight of carbon in the product.
[0091]
While stirring, the vanadium-solution / carbon-black mixture was reheated to boiling point.
[0092]
Dark H₂SO₄9.6 ml of deionized H₂O diluted in 30-40 ml and the diluted acid was added to the boiling composition with stirring. The H / V ratio was 2. The resulting mixture was kept boiling while stirring for 15 minutes.
[0093]
Then, the beaker was removed from the heat source and stirred for 1 hour. The solid was allowed to settle for 5 minutes. The warm supernatant was decanted.
[0094]
The precipitate is washed with H₂Reslurry in a fresh aliquot of O for about 1 minute. The precipitate was again allowed to settle for about 10 minutes, and the supernatant was decanted. A second aliquot of fresh water was added and the washing and solids separation steps were repeated.
[0095]
The washed, sedimented precipitate was collected on filter paper by suction filtration. The filter cake was chopped into small pieces and dried in air for about 64 hours, followed by drying under an IR heat lamp for 4 hours. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0096]
After pulverization to produce a powder, the powder was sieved through a 200 mesh sieve to obtain a powder suitable for producing a cathode. The product was found by SEM to be non-fibrous up to 30,000 times magnification.
[0097]
Two electrodes were made with different binders. One electrode was fabricated as described in Example 1 to form a 120 micrometer thick electrode. It was incorporated into a coin battery as in Example 1. The initial discharge capacity was found to be 350 mAh / g.
[0098]
For the other electrodes, 1.000 g of powder was combined with 0.1000 g of MMM Super P carbon black, 0.15539 g of Kynarflex manufactured by Elf Atochem, 0.285 g of dibutyl phthalate, and 4.6 ml of acetone. The mixture was placed in a capped glass vial and shaken on a mechanical shaker for 15 minutes.
[0099]
The cathode paste was spread on a sheet of Teflon® FEP and stretched using a doctor blade with a 10 mil gap to form a film. After evaporation of the acetone, dibutyl phthalate was extracted with dimethyl ether. The dried film (consisting of active powder 79.8% by weight, binder 12.2% by weight, and carbon black 8% by weight) was inserted between Kapton® sheets and calender rolled at 2000 psi and 110 ° C. To form a reinforced electrode sheet suitable for use as a cathode in a lithium battery. The thickness of the sheet was 86 micrometers.
[0100]
The cathode sheet disk was cut with a punch and assembled into a coin battery as described in Example 1. The initial discharge capacity was found to be 357 mAh / g.
[0101]
Example 17
The electrode of Example 16 was used as a cathode of a Li-ion electrochemical cell. The anode consisted of lithiated graphite. This formed a coin cell by reacting a thin disk of Li metal and graphite at room temperature.
[0102]
6.0000 g of graphite powder {MCMB25-28 (Osaka Gas Company, Japan)}, 0.1936 g of Super P carbon black (MMM SA Carbon, Brussels, Belgium), and 0.1936 g of a 4% by weight solution of EPDM rubber in cyclohexane. Combined with 452 g. Further, 2.0 mL of cyclohexane was added to improve the fluidity. The mixture was placed in a capped glass vial and shaken on a mechanical shaker for 15 minutes to form a graphite paste.
[0103]
The graphite paste was applied to a sheet of Teflon® FEP (DuPont @ Company, Wilmington, DE) and stretched using a doctor blade with a 40 mil gap to form a film. After drying, a film (consisting of graphite 93% by weight, binder 4% by weight, and carbon black 3% by weight) was inserted between Kapton® polyimide sheets (DuPont) and calendered at 2000 psi and 110 ° C. And hot pressing to form a reinforced electrode sheet. The thickness of the sheet was about 295 micrometers.
[0104]
Disks of cathode, graphite, Li metal, and fiberglass separator were cut with a punch. The graphite and Li metal were placed in a glove box in a dry nitrogen environment. In a glove box, the cathode and separator pieces were replaced with LiPF in EC / DMC (ethylene carbonate / dimethyl carbonate).₆Immersed in an electrolyte solution consisting of and then stacked on a coin cell pan along two graphite discs and one Li disc (the Li disc has a thickness of about 100 micrometers) to form a 2325 {Coin} Cell {Crimper} System ( Sealed under pressure using National Research Research Council of Canada.
[0105]
The coin cell was left for 90 hours before testing. The amounts of graphite and Li metal are approximately LiC₁₀And the same Li-graphite composition. This was thought to indicate that no Li metal would remain in the coin cell prior to testing. Coin cells were tested according to the standard methods used herein. However, the voltage range is 1.5-4.0 volts to 1.4-3.9 volts since the voltage of the lithium-graphite anode is observed to be about 0.09 volts for Li metal. Was adjusted to. In the above non-optimized coin cell assembly, 92% of the initial discharge capacity obtained in Example 16 was obtained for the Li-ion battery of this example.
[0106]
Example 18
Example 10 was repeated. However, the heated solution was cooled to room temperature before the acid was added.
[0107]
After 10 minutes, only a small amount of solids had formed. More solids were observed after 1 hour. Even more solids formed after stirring overnight. The supernatant was found to contain soluble unprecipitated vanadium. The supernatant was decanted and the solid was slurried with fresh deionized water by stirring for about 1 minute. The precipitate was allowed to settle for about 10 minutes. The supernatant wash was pH 3 as measured on a multicolored pH paper strip. The washed, sedimented precipitate was collected on filter paper by suction filtration. The filter cake was chopped into small pieces and dried in air overnight. As a result, 14 g was obtained.
[0108]
The formation of the desired product was confirmed by X-ray powder diffraction. (NH₄)_0.14V₂O₅(SO₄)_0.07・ 1.1H₂The composition of O was obtained from thermogravimetric analysis. Based on this composition, a product yield of 77% was calculated. In the X-ray powder diffraction pattern, V₂O₅・ NH₂Only the O line was shown.
[0109]
Then, the obtained V₂O₅・ NH₂The dry powder of O was processed and combined as described in Example 1 to form a 120 um thick electrode. It was incorporated into a coin battery as in Example 1. The Li capacity was found to be 330 mAh / g according to the method described above.
[0110]
Example 19
NH₄VO₃20.1 g of deionized H in a 1 liter Pyrex beaker while stirring with a Teflon coated magnetic stir bar.₂O was added to about 900 ml. The contents of the beaker were heated to boiling to form a solution. Subsequently, the solution was cooled to room temperature. While stirring, concentrated H₂SO₄(H₂19.2 ml of O (diluted with 50 ml) was added to the solution. The acid proton to vanadium ratio was 4. After 4 hours, only traces of solids had formed.
[0111]
Example 20
Example 10 was repeated. However, the temperature of the solution was reduced to 45 ° C. before the acid was added.
[0112]
The reaction was kept at about 45 ° C. overnight. The acid proton to vanadium ratio was 2. The supernatant was found to contain some soluble unprecipitated vanadium. The supernatant was decanted and the solid was slurried with fresh deionized water by stirring for about 1 minute. The precipitate was allowed to settle for about 10 minutes. The supernatant had a pH of 2-3 as measured on a piece of multicolor pH paper. The washed, sedimented precipitate was collected on filter paper by suction filtration. The filter cake was chopped into small pieces and dried in air to give 15.8 g of product. In X-ray powder diffraction, the product consists mainly of the desired substance plus some (NH₄)₂V₆O₁₆It was shown to consist of. V₂O₅・ H₂The estimated yield of O is 10% (NH₄)₂V₆O₁₆75-80% assuming impurities.
[0113]
The resulting dry mixed phase powder was then processed and combined as described in Example 1 to form a 120 um thick electrode. It was incorporated into a coin battery as in Example 1. The lithium capacity was found to be 329 mAh / g according to the method described above.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an initial discharge capacity determined as a function of an H / V ratio in Examples 1 to 16.
FIG. 2a shows a scanning electron micrograph at 10,000 magnification for the non-fibrous product of Example 10.
FIG. 2b shows a scanning electron micrograph at 30,000 magnification for the non-fibrous product of Example 10.
FIG. 3a shows a scanning electron micrograph at 10,000 magnification for the non-fibrous product of Example 16.
FIG. 3b shows a scanning electron micrograph at 30,000 magnification for the non-fibrous product of Example 16.
FIG. 4 shows an initial discharge curve and a first recharge curve. This indicates milliamp-hour / g of the electrode active material: voltage measured in Example 10.
FIG. 5 shows an initial discharge curve and a first recharge curve. This indicates milliamp-hour / g of the electrode active material: voltage measured in Example 16.

Claims (13)

_{M x V 2 O 5 A y} · nH 2 O ( wherein, M is ^{_{NH 4 +, Na +, K}} +, Rb +, is selected from Cs ⁺ and Li ⁺ the group consisting, A is _NO ³ -, SO ₄ ^-2 and Cl ^- is selected from the group consisting of a method of manufacturing a 0 <x <0.7,0 <y < 0.7, and a 0.1 <n <2),
Combining the vanadate with water to form a solution, and adding a strong inorganic acid to the solution, wherein the molar ratio of acid proton to vanadium is in the range of 0.70: 1 to 6: 1;
_{M x V 2 O 5 A y} · nH 2 O production method comprising. 2. The method of claim 1, further comprising the step of heating the solution to a temperature in the range of 80 <0> C to the boiling point of the solution before adding the strong inorganic acid. 2. The method of claim 1, further comprising the step of dispersing elemental carbon in the solution before adding the acid. The method of claim 1, wherein said molar ratio is in the range of 1: 1 to 4: 1. The method of claim 1 wherein the concentration of vanadate in said solution is in the range of 0.1 to 1 molar. The concentration of carbon in the final product The method of claim 3 1-12% by weight of the total weight of carbon _{+ M x V 2 O 5 A} y · nH 2 O. The concentration of the carbon in the final product The method of claim 3 which is 4 to 8% by weight of the total weight of carbon _{+ M x V 2 O 5 A} y · nH 2 O. During non-fibrous _{M x V 2 O 5 A y} · nH 2 O ( wherein, M is ^{_{NH 4 +, Na +, K}} +, Rb +, is selected from Cs ⁺ and Li ⁺ the group consisting, A is NO ₃ ^-, _SO ^{4 -2} and Cl ^- is selected from the group consisting of, a 0 <x <0.7, as well as compositions comprising 0.1 <n <a 2.0), 315~400mAh / G initial discharge capacity. Further comprising a elemental carbon of 1 to 12% by weight of the total weight of carbon _{+ M x V 2 O 5 A} y · nH 2 O, the Sai該 _{M x V 2 O 5 A y} · nH 2 O Carbon 9. The composition according to claim 8, which is present as an overcoat. Wherein said composition The composition of claim 9 comprising 4-8 wt% of elemental carbon in the total weight of carbon _{+ M x V 2 O 5 A} y · nH 2 O. An electrode comprising the composition according to claim 8. An electrochemical cell comprising the electrode according to claim 11. 13. The electrochemical cell according to claim 12, which is in the form of a lithium or lithium-ion battery.

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