Source: sabon shugaban makamashi, by
Abstract: a halin yanzu, lithium salts a kasuwanci lithium-ion baturi electrolyte yawanci LiPF6 da LiPF6 sun ba da electrolyte kyakkyawan aikin electrochemical, amma LiPF6 yana da rashin zafi da kuma sinadarai kwanciyar hankali, kuma yana da matukar damuwa ga ruwa.
A halin yanzu, gishirin lithium a cikin batirin batirin lithium-ion na kasuwanci galibi LiPF6 ne kuma LiPF6 sun ba wa electrolyte kyakkyawan aikin lantarki.Koyaya, LiPF6 yana da ƙarancin yanayin zafi da kwanciyar hankali, kuma yana kula da ruwa sosai.A karkashin aikin karamin adadin H2O, abubuwan acid irin su HF za su lalace, sannan za a lalata abubuwa masu kyau, kuma za a narkar da abubuwan ƙarfe na sauye-sauye, kuma za a yi ƙaura saman na'urar lantarki don lalata fim ɗin SEI. , Sakamakon ya nuna cewa fim din SEI ya ci gaba da girma, wanda ke haifar da ci gaba da raguwar ƙarfin baturan lithium-ion.
Don shawo kan waɗannan matsalolin, mutane sun yi fatan cewa gishirin lithium na imide tare da ingantaccen H2O da ingantaccen yanayin zafi da kwanciyar hankali, irin su lithium salts kamar LiTFSI, lifsi da liftfsi, an iyakance su ta hanyar abubuwan farashi da anions na gishirin lithium. kamar LiTFSI ba za a iya warwarewa don lalatawar Al foil, da sauransu, LiTFSI lithium gishiri ba a yi amfani da su a aikace.Kwanan nan, VARVARA sharova na dakin gwaje-gwajen HIU na Jamus ya samo wata sabuwar hanya don aikace-aikacen salts na lithium imide a matsayin abubuwan da suka hada da electrolyte.
The low m na graphite korau electrode a Li-ion baturi zai kai ga bazuwar electrolyte a kan ta surface, forming passivation Layer, wanda ake kira SEI film.Fim ɗin SEI na iya hana electrolyte daga bazuwa a kan mummunan farfajiya, don haka kwanciyar hankali na fim ɗin SEI yana da tasiri mai mahimmanci akan yanayin sake zagayowar batirin lithium-ion.Ko da yake ba za a iya amfani da gishirin lithium irin su LiTFSI a matsayin solute electrolyte na kasuwanci na ɗan lokaci ba, an yi amfani da shi azaman ƙari kuma ya sami sakamako mai kyau.Gwajin VARVARA sharova ya gano cewa ƙara 2wt% LiTFSI a cikin electrolyte na iya haɓaka aikin sake zagayowar batirin lifepo4/ graphite yadda ya kamata: hawan keke 600 a 20 ℃ kuma raguwar ƙarfin yana ƙasa da 2%.A cikin ƙungiyar kulawa, ana ƙara electrolyte tare da ƙari na 2wt% VC.A ƙarƙashin yanayi guda, raguwar ƙarfin baturin ya kai kusan 20%.
Don tabbatar da tasirin abubuwan ƙari daban-daban akan aikin batirin lithium-ion, ƙungiyar lp30 mara kyau (EC: DMC = 1: 1) ba tare da ƙari ba kuma ƙungiyar gwaji tare da VC, LiTFSI, lifsi da liftfsi an shirya su ta hanyar varvarvara sharova. bi da bi.An kimanta aikin waɗannan electrolytes ta maɓallin rabin tantanin halitta da cikakken tantanin halitta.
Hoton da ke sama yana nuna maƙallan voltammetric na electrolytes na rukunin kula da babu komai da ƙungiyar gwaji.A lokacin aikin ragewa, mun lura cewa a bayyane kololuwa na yanzu ya bayyana a cikin electrolyte na rukunin da ba komai a kusan 0.65v, daidai da raguwar lalatawar EC.Ƙwararrun ɓarna na yanzu na ƙungiyar gwaji tare da ƙari na VC ya canza zuwa babban yuwuwar, wanda ya fi dacewa saboda ƙarancin wutar lantarki na ƙarar VC ya fi na EC, Saboda haka, ɓarna ya fara faruwa, wanda ke kare EC.Koyaya, ma'aunin voltammetric na electrolyte da aka ƙara tare da LiTFSI, lifsi da littfsi additives ba su da bambanci sosai da na rukunin da ba komai ba, wanda ke nuni da cewa abubuwan ƙari na imide ba za su iya rage ruɓewar sauran ƙarfi na EC ba.
Hoton da ke sama yana nuna aikin electrochemical na graphite anode a cikin electrolytes daban-daban.Daga ingancin cajin farko da fitarwa, ƙimar coulomb na ƙungiyar mara kyau shine 93.3%, ingantaccen ƙarfin farko na electrolytes tare da LiTFSI, lifsi da liftfsi sune 93.3%, 93.6% da 93.8%, bi da bi.Duk da haka, na farko yadda ya dace na electrolytes tare da VC ƙari ne kawai 91.5%, wanda shi ne yafi saboda a lokacin farkon lithium intercalation na graphite, VC bazu a saman graphite anode da kuma cinye mafi Li.
Abun da ke ciki na fim ɗin SEI zai yi tasiri mai girma akan haɓakar ionic, sa'an nan kuma ya shafi ƙimar ƙimar batirin Li ion.A cikin gwajin aikin ƙimar, an gano cewa electrolyte tare da lifsi da liftfsi additives suna da ɗan ƙaramin ƙarfi fiye da sauran electrolytes a cikin babban fitarwa na yanzu.A cikin gwajin sake zagayowar C / 2, aikin sake zagayowar na duk electrolytes tare da ƙari na imide yana da kwanciyar hankali sosai, yayin da ƙarfin lantarki tare da ƙari na VC yana raguwa.
Domin kimanta da kwanciyar hankali na electrolyte a cikin dogon lokaci sake zagayowar na lithium-ion baturi, VARVARA sharova kuma shirya LiFePO4 / graphite cikakken cell tare da button cell, da kuma kimanta da sake zagayowar yi na electrolyte da daban-daban Additives a 20 ℃ da 40 ℃.Ana nuna sakamakon kimantawa a cikin jadawalin da ke ƙasa.Ana iya gani daga tebur cewa ingancin electrolyte tare da ƙari na LiTFSI yana da mahimmanci fiye da haka tare da ƙari na VC a karon farko, kuma aikin hawan keke a 20 ℃ ya fi girma.Matsakaicin riƙe ƙarfin lantarki tare da ƙari na LiTFSI shine 98.1% bayan zagayowar 600, yayin da ƙimar riƙewar ƙarfin lantarki tare da ƙari na VC shine kawai 79.6%.Koyaya, wannan fa'idar tana ɓacewa lokacin da ake yin keken lantarki a 40 ℃, kuma duk masu amfani da lantarki suna da irin wannan aikin hawan keke.
Daga binciken da aka yi a sama, ba shi da wahala a ga cewa za a iya inganta aikin sake zagayowar batirin lithium-ion sosai lokacin da ake amfani da gishirin lithium imide azaman ƙari.Domin yin nazarin tsarin aiki na abubuwan ƙarawa kamar LiTFSI a cikin batir lithium-ion, VARVARA sharova yayi nazari akan abun da ke cikin fim ɗin SEI wanda aka kafa akan saman graphite anode a cikin electrolytes daban-daban ta XPS.Hoton da ke gaba yana nuna sakamakon binciken XPS na fim ɗin SEI da aka kafa a saman graphite anode bayan na farko da na 50th.Ana iya ganin cewa abun ciki na LIF a cikin fim ɗin SEI da aka kafa a cikin electrolyte tare da ƙari na LiTFSI yana da mahimmanci fiye da haka a cikin electrolyte tare da ƙari na VC.Ƙarin ƙididdigar ƙididdiga na abubuwan da ke tattare da fim ɗin SEI ya nuna cewa tsari na LIF abun ciki a cikin fim din SEI shine lifsi> liftfsi> LiTFSI> VC> rukunin mara kyau bayan sake zagayowar farko, amma fim ɗin SEI ba ya canzawa bayan cajin farko.Bayan hawan keke na 50, abun ciki na LIF na fim ɗin SEI a cikin lifsi da liftfsi electrolyte sun ragu da 12% da 43% bi da bi, yayin da LIF abun ciki na electrolyte da aka kara tare da LiTFSI ya karu da 9%.
Gabaɗaya, muna tunanin cewa tsarin membrane na SEI ya kasu kashi biyu: Layer inorganic Layer da na waje na kwayoyin halitta.Layer na inorganic ya ƙunshi LIF, Li2CO3 da sauran abubuwan da ke cikin inorganic, waɗanda ke da mafi kyawun aikin lantarki da haɓakar ionic mafi girma.A m Organic Layer ne yafi hada da porous electrolyte bazuwa da kuma polymerization kayayyakin, kamar roco2li, PEO da sauransu, wanda ba shi da wani karfi kariya ga electrolyte, Saboda haka, muna fata cewa SEI membrane ƙunshi more inorganic aka gyara.Imide additives na iya kawo ƙarin abubuwan haɗin LIF na inorganic zuwa membrane na SEI, wanda ke sa tsarin tsarin membrane na SEI ya fi kwanciyar hankali, zai iya hana lalacewar electrolyte a cikin tsarin sake zagayowar baturi, rage yawan amfani da Li, kuma yana inganta aikin sake zagayowar baturi.
A matsayin abubuwan da ake ƙara electrolyte, musamman abubuwan LiTFSI, gishirin lithium imide na iya haɓaka aikin baturi sosai.Wannan shi ne yafi saboda gaskiyar cewa fim din SEI da aka kafa a saman graphite anode yana da karin LIF, mafi ƙarancin kuma mafi kwanciyar hankali na SEI, wanda ya rage bazuwar electrolyte kuma yana rage juriya na dubawa.Koyaya, daga bayanan gwaji na yanzu, ƙari na LiTFSI ya fi dacewa don amfani a zafin jiki.A 40 ℃, LiTFSI ƙari ba shi da fa'ida a bayyane akan ƙari na VC.
Lokacin aikawa: Afrilu-15-2021