边锋游戏

关注硅和电解液之间的自发反应
发布时间:2019-07-08 10:45:20
关键词:动力电池锂电池

关注硅和电解液之间的自发反应


【背景】

GUISHIYIZHONGXIANGDUIHUOPODEYUANSU,HENRONGYIYUXUDUOHUAHEWUFANYING,GUIYUYANGZAIJIHAOMIAONEIFASHENGFANYING,XINGCHENGYICENGBOBODEYANGHUAMO;HAIKEZAIJIHAOMIAONEIYULILIZIDIANCHIDIANJIEYEFASHENGFANYING。QIZHONG,WUYANGGUI(YIXIAJIANCHENGGUI)KELIYUDIANCHIDIANJIEYEDEFANYINGSHOUWENDU、DIANJIEYE、BAOLUYUDIANJIEYEDEJINGMIAN、GUIBIAOMIANDECUCAODUHEQUEXIANYINGXIANG。ZAIGUIDETIJIPENGZHANGHESHOUSUOGUOCHENGZHONG,SEIXINGCHENGLIEWEN,DAOZHIYUDIANJIEYEZHIJIEJIECHU,ZAIZHEIXIEXINXINGCHENGDELIEFENGCHUXINGCHENGXINDESEI。SEIDEXINGCHENGGUOCHENGHEGUI/DIANJIEYEDEZHIJIEHUAXUEFANYINGZHIJIANCUNZAIJINGZHENG,MEIGEGUOCHENGDEGONGXIANQUJUEYUTAMENDEDONGLIXUEHELILIZIZAIGUI/DIANJIEYEJIEMIANDENONGDU。

 

【NEIRONGJIANJIE】

边锋游戏JINRI,YISELIETELAWEIFUDAXUEDEE. PeledJIAOSHOUKETIZUSHOUCIYANJIULEWUYANGHUAGUIHEDIANJIEYEZHIJIANHUAXUEFANYINGDEDONGLIXUEYIJIZAIZHEIXIEFANYINGGUOCHENGZHONGXINGCHENGDEBIAOMIANMODEZUCHENGHEXINGTAI。FAXIANZHEIXIEFANYINGDEDONGLIXUEHENKUAI,ZAIJIHAOMIAONEIXINGCHENGJINAMIDEDUNHUAMO,BINGZAIYUE30MIAONEIWANCHENGDUNHUA。XPSYANJIUXIANSHIDUNHUAMOYOUDAYOUJIFENZIHUOHANYOUC-O,C=O,C-FxHEO-C-FBUFENDEJUHEWU,SiFx,SiOxFy,YIJIYIXIESiO2HESHAOLIANGDELiFZUCHENG,QIZHONGJINHANYOUHENLIANGDELi。GAIYANJIUCHENGGUOYIUnderstanding the Spontaneous Reactions between Oxide-Free Silicon and Lithium-Battery ElectrolytesWEITIFABIAOZAIGUOJIQIKANJournal of The Electrochemical SocietySHANG。

 

【NEIRONGGAISHU】

3.1 实验装置及相关测试

边锋游戏YANJIUGUIYULIDIANCHIDIANJIEYEZHIJIANDEHUAXUEFANYINGJUYOUZHONGYAOYIYI。BENGONGZUODEMUDESHIYANJIUYUANSHI(WUYANG)GUIYULIDIANCHIDIANJIEYEZHIJIANDEHUAXUEFANYINGDONGLIXUE,YIJIGUIBIAOMIANSUOXINGCHENGBOMODEZUCHENGHEXINGMAO。DIANHUAXUEDIANCHI(TU1)YOUYIGETXINGGUANJIETOU(a),GUIJUXINGZHIJIA(b),DINGBUYOUJUSIFUYIXIMAODEBUXIUGANGBANG(c)HELICANBIDIANJI(d)。ZUZHUANGWANCHENGHOU,DIANJIECHIZHONGTIANCHONG1.5 mLDIANJIEYE。JIANGGUIHELICANBIDIANJILIANJIEDAOCESHIZHUANGZHI(VMP3)SHANG,BINGGENZONGKAILUDIANYA(OCV) 15 min。WEIFANGZHIDAODIANGUIZHIJIAYUDIANJIEYEJIECHU,DIANCHISHEZHICHENG45°JIAO,ZHIYOUGUIPIANHEJINSHULIJINZAIDIANJIEYEZHONG。DIANYAWENDINGHOU,ZAI2.8~3.15VZHIJIANDESHUJUCAIJISULVTIGAODAOMEI0.6 msCAIYANGYICI。JIMIAOZHONGHOU,YANHUAHENXIANJIANGGUIDUANKAI,TONGSHIJIXUMEI0.6 msDIANYACAIYANGYICI,JIEGUORUBIAO1HETU2SUOSHI。SUIHOU,JIANGLIANGGEJUXINGGUIYANGPINCONGDIANCHIZHONGQUCHU,YONGDMCQINGXI,ZHENKONGGANZAO,RANHOUJINXINGXPSHUOSEMCESHI。QIZHONG,XPSCAIYONGYALIZIJIANSHEFA,YI0.5 nm/minDEJIANSHESUDU(YISiO2/SiWEIJIZHUN)HUODESHENDUPOUMIAN。


图1. 电化学电池由T形管接头(a),硅矩形支架(b),顶部有聚四氟乙烯帽的不锈钢棒(c)和锂参比电极(d)组成。


3.2 测试结果分析

TU2WEISHIYANGUOCHENGZHONGSi-LiDIANCHIDIANYADEBIANHUAQINGKUANG。QIEDUANQIANDEOCVYUEWEI3 V,MEI0.6 msCAIYANGYICI。BIXUZHUYIDESHI,QIEDUANSHISHOUGONGWANCHENGDE,QIEDUANLIHEQIEDUANSHIJIANBUKEZHONGFU。BIAO1ZONGJIELEZAIJIZHONGDIANJIEYEZHONGDAPOJUXINGGUIDUIQIDIANYADEYINGXIANG。


JICHUDIANJIEYEWEI1M LiPF6RONGYUEC:DMC [1:1]ZHONG,FECSHILILIZIDIANCHIDIANJIEYEDEZHONGYAOTIANJIAJI,YANJIULETIANJIA2%HE15%FECDUIDIANCHIXINGNENGDEYINGXIANG。DUANKAIHOUDEDIANYAXIAJIANGFEICHANGKUAI,BUDAO1 ms(TU2),QIEDIANYAXIAJIANG(V)BINGBUSHIWANQUANKEZHONGXIANDE,ZAITONGYIDIANJIEYEZHONG,BUTONGYANGPINDEDIANYACHAYIJIAODA,ZAI59~183mVZHIJIAN,BIAOZHUNPIANCHAJIAODA(BIAO1)。YUE1 msHOU,DIANYAKAISHISHANGSHENG,JIEJINYUYUANSHIOCV (TU2,BIAO1),BIAOMINGFEICHANGKUAISUDEDUNHUA,YOUWUYANGGUIHENGJIEMIANYUDIANJIEYEZHIJIANDEZIFAFANYINGZAOCHENG。ZAI15% FECDIANJIEYEZHONGDUNHUASUDUGENGKUAI,SHUOMINGFECDUIGUIDEFANYINGHUOXINGJIAOGAO。PODUANQIANPINGJUNOCV (BIAO1)ZUNXUN15%FEC>2%FEC >WUFECDESHUNXU(3.12,3.08,3.01V),OCVSHUNXUYUFECDEYANGHUANENGLIYOUGUAN,FECDEYANGHUANENGLIQIANGYUECHEDMC。KAILUDIANYACHASUIFECNONGDUDEZENGJIAERZENGDA,ZAIBUHANFEC、2%FECHE15%FECDEDIANJIEYEZHONG,GUIDEKAILUDIANYACHAFENBIEWEI59 mv、128 mvHE183 mV。


边锋游戏ZHEIXIEJIEGUOBIAOMING,YUMEIYOUFECDEDIANJIEYEXIANGBI,HANFECDIANJIEYEJUYOUGENGGAODEFANYINGHUOXING。DUIDMCXIDIHOUZHENKONGGANZAODESHIYANGJINXINGSEMYANJIU,TU3XIANSHILEPOSUIDEHENGJIEMIANJUXING,WUYANGGUIJUXINGDEHENGJIEMIANYUDIANJIEYEKUAISUFANYING,XINGCHENGDUNHUAMO。ZAIWUFECYANGPINDEBIAOMIAN,KEYIKANDAOGULIDEFANYINGCHANWU“DAO”,2%HE15%FECYANGPINDEBIAOMIANJIHUWANQUANBEIYICENGHOUHOUDEFANYINGCHANWUSUOFUGAI,ZHEIYIJIEGUOYUXPSCELIANG2%HE15% FECYANGPINBIAOMIANJIAOHOUDEBOMOYIZHI(TU4)。


图2. Si-Li电池在(a)无FEC电解液,(b)含2% FEC电解液和(c)含15%FEC电解液断开时的电压分布。


图3. 硅矩形在(a)无FEC电解液,(b)含2% FEC电解液和(c) 含15% FEC电解液断裂的SEM图


BIAO1. GUIPIANQIEDUANDUIDIANCHIDIANYADEYINGXIANG(LiZUOWEICANBIDIANJI)。

BIAO2. XPSCEDINGLEBUTONGJIANSHESHIJIANXIAPOSUIGUIBIAOMIANYUANSUDEHANLIANG


边锋游戏YONGDMCXIDIYANGPIN,ZHENKONGGANZAOHOU,YONGXPSYANJIUDUNHUACENGDEZUCHENG(TU4,5)。BIAO2WEISANZHONGDIANJIEYEZHONGJUXINGGUIDUANLIEHOUXINGCHENGDEDUNHUAMOBIAOMIANYUANSUHANLIANG,ZHUYAOCHENGFENSHIFU、TANHEYANG,LIDEHANLIANGXIAOYU4%,LINDEHANLIANGXIAOYU0.13%KEYIHULVEBUJI(BIAOZHONGMEIYOUXIANSHI)。LINDEQUEFASHUOMINGYANGPINZHONGLiPF6BEIYOUXIAODEXIDI。GUIDEXINHAOYOULIANGZHONGLAIYUAN,YIZHONGSHIDUNHUAMOZHONGDEGUI,LINGYIZHONGSHIDUNHUAMOXIADEGUI。JIANSHEKESHIQIANGUIDEHANLIANGSUIDIANJIEYEZHONGFECDEHANLIANGZENGDAERJIANXIAO(BIAO2),BIAOMINGLEDUNHUAMOSUIDIANJIEYEZHONGFECDEZENGJIAERZENGDA。WUFEC、2% FECHE15%FECSHIYANGDUNHUAMOBIAOMIAN(KESHIQIAN,BIAO2HETU4)FUHANLIANGFENBIEWEI10、21HE12%,BIAOMINGWUYANGGUIYULiPF6HEFECFANYINGSHENGCHENGHANFUWUZHI。DUNHUAMOBIAOMIANDETAN、YANGHANLIANG(JIANSHEQIAN,BIAO2HETU4)SUIDIANJIEYEZHONGFECNONGDUDEZENGJIAERZENGJIA,ZHEISHIWUYANGGUIYUFECFANYINGDEYOUYIZHENGJU。


边锋游戏TU4WEIJIYEHEHAN2%FEC、15% FECDEDUNHUAMOZHONGYUANSUDESHENDUFENBUTU。ZAIBUHANFECHE2% FECYANGPINKESHI0.5 minHOU,CHUGUIWAIDESUOYOUYUANSUDEHANLIANGDOUXIAJIANGDAO13%YIXIA,GUIHANLIANGSHANGSHENGDAO87-88%。CESHIDEJIANSHESULV(JIYUSiO2)WEI4.25nm/min,YINCIBUHANFECHE2%FECYANGPINSHANGDUNHUAMODEHOUDUZHIYOU1-2 nm,ZHEIZHONGFEICHANGBODEDUNHUACENGKEYITINGZHIHUODADAJIANHUANWUYANGGUIHEDIANJIEYEZHIJIANDEFANYING。15%FECYANGPINDUNHUACENGHOUDUDAYUQITALIANGGEYANGPIN,JISHIJIANSHE2 minHOU,GUIHANLIANG(BIAO2)YEZHIYOU66%(ERDUIYUBUHANFECHE2%FECYANGPIN,GUIDEHANLIANGWEI93-94%),BIAOMIANDEZHUDAOYUANSUSHITAN,22-32%(BIAO2HETU4)。


图4. 用XPS测量在(a)无FEC电解液,(b)含2% FEC电解液和(c)含15%FEC电解液中形成的钝化膜中元素溅射过程中的深度剖面。其中:棕色-Si,蓝色-C,黄色-F,红色-O,绿色-Li。


边锋游戏TU5WEIDUNHUAMOZAIKESHIQIANDEGAOFENBIANLVXPSGUANGPU,DUNHUAMOXINGCHENGYUJITIDIANJIEYE(ZONGSE)YIJIHANYOU2% FEC(LVSE)、15% FEC(LANSE)DEDIANJIEYEZHONG。TU5aXIANSHIBUHANFECHEHANYOU2% FECDEYANGPINZHIYOUYIGEYUE100eVDEFENG,DUIYINGYUGUI,FENGDEYANSHENKENENGBIAOMINGCUNZAISiOx (102 eV)HUOSiC (100.5 eV)。15% FECYANGPINDEXPSPUZAI104 eVZUOYOUYOULINGYIGEXIAOFENG,ZHEIYUSiOxFyHESiO2YOUGUAN。TU5bWEIKESHIQIANDUNHUAMOZHONGTANDEGAOFENBIANLVXPSGUANGPU,ZHUFENGYUEWEI285.5eV,WEIC-CHEC-HJIAN,BIAOMINGCUNZAIFEIHUIFAXINGDAYOUJIFENZIHUOJUHEWU。SUOYOUDEYANGBENDOUYOUYIGEYUC=OWUZHONGCUNZAIXIANGGUANDE288eVDEJIANFENGHELINGYIGEYUC-OWUZHONGCUNZAIXIANGGUANDE286eVDEJIANFENG,ZHIYOU2%DEFECYANGPINZAI295.5HE294eVCHUYOUYIGEJIAODADEFENG,SHUYUC-Fx。JIEGUOBIAOMING,ZAIBUHANFECHEHANYOU15% FECDEYANGPINZHONG,MOZHONGHANYOUYANGHANLIANGJIAODIDEJUHEWU,15% FECMOZHONGHANFUJUHEWUJIAODUO。JIEGUOBIAOMING,XINGCHENGLEBAOHEJUXITINGHEBUBAOHEJUXITING。ZAIECJIDIANJIEYEZHONGXINGCHENGDEBIAOMIANMOZHONGFAXIANLEJIAOGAODEHANYANGBIAOMIANZHONGLEI,JITANSUANYAN(ROCO2Li)、KENENGDECHUNYANGHUAHEWUYIJIJUMI(ROLi,?CH2O?),HANFECDIANJIEYEZHONGLiFHANLIANGJIAOGAO。YUCHUANTONGDESEIZAILIHUAHUAGUOCHENGZHONGXINGCHENGDEQINGKUANGBUTONG,LiFHANLIANGFEICHANGDI,MEIYOUTANSUANYAN,ZHEIBIAOMINGHAIYUANJIZHIBUTONG。


边锋游戏TU5cWEIKESHIQIANDUNHUAMOZHONGFUYUANZIDEGAOFENBIANLVXPS。SANGEYANGPINYOUBUTONGDEJIANNENGFENGZHI,2% FECYANGPINDEFENGZHIWEI690 eV,ZHEIYUC-FxHEO-C-FYOUGUAN;15% FECYANGPINZAI686 evCHUYOUYIGEFENGZHIDUIYINGYUSiFx,ERBUHANFECDEYANGPINZAILIANGZHEZHIJIANYOUYIGEFENGZHI(688 eV),ZHEIBIAOMINGSHANGSHUWUZHONGDEZUHE。TU5dWEIKESHIQIANDUNHUAMOZHONGYANGDEGAOFENBIANLVXPS。SUOYOUYANGPINDEZHUFENGDOUZAI532/3eVZUOYOU,SHUYUC-OHE/HUOO-C-O,ZAI534eVCHUYOUYIGEYUC=OYOUGUANDEJIANFENG。2%FECYANGPINZAI537eVYOUYIGEJIAODADEFENG,ERBUHANFECDEYANGPINYOUYIGEXIAODEJIANFENG,SHUYUO-C-F,ZHEIYIFAXIANDEDAOLE2% FECYANGPINZHONGFUHANLIANGGAODEZHICHI。


图5. 在无FEC电解液(棕色),含有2%FEC电解液(绿色)和15% FEC电解液(蓝色) 形成的钝化膜,溅射前的高分辨率XPS光谱(a)硅,(b)碳,(c)氟和(d)氧。


GENJUXPSCELIANGDEJIEGUO,WUYANGGUIYULIDIANCHIDIANJIEYEFANYINGXINGCHENGDEDUNHUAMOYOUHANYOUC-O、C=O、C-FxHEO-C-Fx、SiFx、SiOxFy、SHAOLIANGSiO2HESHAOLIANGLiFDEDAXINGYOUJIFENZIHUOJUHEWUZUCHENG。LINHELIDEHANLIANGJIAODI,SHUOMINGDANZHIGUIZHUYAOYURONGJIFANYING,TEBIESHIYUFECFANYING,ERYULiPF6FANYINGBUDA。ZHEIBIAOMINGYUSEIZHONGJUHEWUDEXINGCHENGJILILEISI,ZHEILIDEJUHEWUSHITONGGUOHAIYUANYINFAJUHEXINGCHENGDE。YIGEHUODUOGEDIANZICONGWUYANGGUIBIAOMIANZHUANYIDAORONGJIFENZI,YINFABINGCUJINQIJUHE。YOUYANJIURENWEIFECZUOWEILIDIANCHIDIANJIEYETIANJIAJIDEZUIDAYOUDIANSHIQIKUAISUHAIYUANYINFAJUHE,ZHEIJIUJIESHILEZAIWUYANGGUIJUXINGBIAOMIANYULIDIANCHIDIANJIEYEJIECHUXINGCHENGDUNHUACENGDEJUHEWUZHONGC-FxHEO-C-FJITUANDEGAOHANLIANG,RENWEISiFxHESiOxFyJITUANSHIYOUGUIYUFECFENZIZHIJIEFANYINGXINGCHENGDE。

 

【JIELUN】

本文首次研究了无氧硅与锂电池电解液之间的化学反应动力学,以及在化学反应过程中形成的硅表面薄膜的组成和形貌。结果表明,这些反应的动力学过程非常快,在几毫秒内就形成了一层非常薄的钝化膜(几纳米),完全钝化大约需要30秒。用XPS和SEM对薄膜的组成和结构进行研究现,该薄膜由含有C-O、C=O、C-Fx和O-C-Fx的有机大分子或聚合物、SiFx、SiOxFy、少量SiO2和少量LiF组成。由于只有少量的锂,它不能作为SEI。作者的下一个目标是发现被原生氧化物覆盖的硅是否也与电解液反应;如果是这种情况,为了避免或尽量减少这种现象,硅阳极电池必须尽可能靠近电解液充电,或使用部分预锂阳极,在第一次充电时形成的SEI将阻止硅阳极与电解液的自发反应。


稿件来源: 能源学人
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