ÐÂÎÅÖÐÐÄ
EWS CENTER
2024-06-04
×÷ÕߣºËÕ骣¬ Çñ½àɽ£¬ ÍõÖ¾Óî.F²ôÔÓ ¸ßÈÝÁ¿Ì¼Í¿²ãÄÉÃ×¹èÑô¼«£ºÆø̬·ú»¯ÖƱ¸ ºÍï®´æ´¢µÄÐÔÄÜ¡£ÎÞ»úÖÊÁÏѧ±¨£¬ 2023£¬ 38£¨8£©£º 947-953 DOI£º10.15541/jim20230009
ÕªÒª
¾ßÓг¬¸ß´¢ï®±ÈÈÝÁ¿µÄ¹èÖÊÁÏÊDZ¸ÊÜÖõÄ¿µÄ¸ßÐÔÄÜï®Àë×Óµç³Ø¸º¼«ÖÊÁÏ, µ«¹èǶï®Ê±¾Þ´óµÄÌå»ýÅòÕÍЧӦʹ֮¿ìËÙʧЧ, ´Ó¶øÏÞÖÆÁËÆäÓ¦ÓÃÐÔÄÜ¡£±¾Ñо¿Ìá³öÒ»ÖÖ¼òÒ׵Ͷ¾µÄÆøÏà·ú»¯ÒªÁìÖƱ¸·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹èÖÊÁÏ¡£Í¨¹ýÔÚÄÉÃ×¹èÍâò°ü¸²¸ßȱÏݶȵķú²ôÔÓ̼²ã, ÒÖÖƹèÖÊÁÏǶï®Ìå»ýÅòÕÍ, Ìṩ¸»ºñµÄï®Àë×ÓÊäÔËͨµÀ, ͬʱÐγɸ»º¬LiFµÄÎȶ¨SEIĤ¡£»ñµÃµÄ·ú²ôÔÓ̼°ü¸²ÄÉÃ׹踺¼«ÔÚ0.2~5.0 A¡¤g-1µçÁ÷ÃܶÈÏÂ, ±ÈÈÝÁ¿´ï1540~ 580 mAh¡¤g-1, Ñ»·200´ÎºóÈÝÁ¿¼á³ÖÂÊ>75%¡£±¾ÒªÁì½â¾öÁ˹Űå·ú»¯¼¼Êõ·úÔ´(ÈçXeF2¡¢F2µÈ)¸ß±¾Ç®¡¢¸ß¶¾ÐÔµÄÎÊÌâ¡£
Òªº¦´Ê£º ï®Àë×Óµç³Ø; ¹è¸º¼«; ·ú²ôÔÓ̼; ÆøÏà·ú»¯·¨
Éú³¤¸ßЧµÄÄÜÔ´´æ´¢ºÍת»¯¼¼ÊõÓÐÖúÓÚʵÏÖ¡°Ì¼´ï·å¡¢Ì¼Öк͡±Ä¿±ê¡£ï®Àë×Óµç³ØÊÇÄ¿Ç°Ó¦ÓÃ×îΪ¹ã·ºµÄ¸ßЧ´¢Äܼ¼ÊõÖ®Ò»[1], µ«ÉÌÒµ»¯Ê¯Ä«¸º¼«´¢ï®ÈÝÁ¿µÍ, ¼«´óÏÞÖÆÁËï®Àë×Óµç³ØÄÜÁ¿ÃܶÈ[2]¡£¹è¾ßÓе͵çλ¡¢´¢Á¿¸»ºñµÈÓŵã, ÇÒÀíÂÛ±ÈÈÝÁ¿(4200 mAh¡¤g-1)Ô¶¸ßÓÚʯī¸º¼«, ±»ÊÓΪȡ´úʯīµÄºòÑ¡¸º¼«ÖÊÁÏ[3]¡£¹èÖÊÁÏ»ùÓÚÓëï®Àë×ӵĿÉÄæºÏ½ð»¯·´Ó¦ÊµÏÖ´¢ï®, µ«ÕâÒ»Àú³ÌÅãͬ¾Þ´óµÄÌå»ý±ä¸ï(~400%), µ¼Öµ缫¿ìËÙ·Û»¯Ê§Ð§, ³ÉΪÖÆÔ¼¹è¸º¼«×ßÏòʵ¼ÊÓ¦ÓõÄÒªº¦Æ¿¾±[3-4]¡£
½üÄêÀ´, Ñо¿Õß¿ª·¢Á˶àÖÖÌáÉý¹è¸º¼«Îȶ¨ÐÔÓëµç»¯Ñ§ÐÔÄܵÄÕ½ÂÔ, Èç: ÄÉÃ×»¯[5]¡¢Óëµ¼µç̼µÈÖÊÁϽṹ¸´ºÏ[6-7]µÈ, ͨ¹ýÔÚ΢¹Û±ê×¼»º½â¹è¸º¼«´¢ï®Ìå»ýÅòÕÍÅãͬµÄ»úеӦÁ¦ÌáÉýÆä½á¹¹Îȶ¨ÐÔ; ¿ª·¢ÐÂÐ͵ç½âÒº»òµç½âÒºÌí¼Ó¼Á, ÌáÉý¹è¸º¼«±í½çÃæ¹ÌÌåµç½âÖʽçÃæÏà(SEI)µÄÎȶ¨ÐÔÓë¿âÂØЧÂÊ[8]; Éú³¤¸ßЧ¾ÛºÏÎïð¤½á¼Á(Èçôȼ׻ùÏËάËØÄÆ¡¢º£ÔåËáÄÆ¡¢¾Û±ûÏ©Ëá»ù¾ÛÂÖÍé[9]µÈ), Ç¿»¯»îÐÔÖÊÁÏÓë»îÐÔÖÊÁÏÖ®¼ä¡¢»îÐÔÖÊÁÏÓëµ¼µçÍøÂçÖ®¼ä¡¢µç¼«Ä¤Ó뼯Á÷ÌåÖ®¼äµÄ½áÐÁ¦[9-10]¡£ÆäÖÐ, ̼°ü¸²ÊÇÌáÉý¹è¸º¼«½á¹¹Îȶ¨ÐÔÓëµ÷±ä±í½çÃæÐÔÖÊ×îÓÐЧµÄÊÖ¶ÎÖ®Ò»[3-4,11], µ«½ôÃÜ°ü¸²µÄ¸ßÎȶ¨Ì¼²ãͬʱҲ»á×è°ï®Àë×ÓÊäÔË, ÏÞÖƹ踺¼«³ä·Ö·¢»ÓÐÔÄÜ¡£
±ðµÄ, ¹è¸º¼«ÔÚÁ¬Ðø³ä·ÅµçÀú³ÌÖеÄÖظ´Ìå»ý±ä¸ïÒ²ÒýÆðSEIĤ²»¾ø¶ÏÁѺÍÖظ´Éú³¤, µ¼Ö»îÐÔï®Óëµç½âÒºÔڵ缫Íâò²»¾øËðºÄ[12]¡£Õë¶ÔÒÔÉÏÎÊÌâ, ±¾Ñо¿Ìá³öÒ»ÖÖ¸ßЧÆøÏà·ú»¯ÒªÁì, Ôڹ踺¼«ÖÊÁÏÍâò°ü¸²¸»º¬·úÔªËصĸßȱÏݶÈÎÞ¶¨ÐÎ̼²ãÒÔÌáÉýÆä½á¹¹Óë½çÃæÎȶ¨ÐÔ¡£ÓëʹÓÃXeF2»òF2µÈ¸ß±¾Ç®¡¢¸ß¶¾ÐÔ·úÔ´µÄ¹Å°å·ú»¯¼¼ÊõÏà±È[13], ±¾Õ½ÂÔÔ½·¢¼òÒ׵Ͷ¾¡£·ú²ôÔÓ̼²ãÔÚÄÉÃ×¹èÖÊÁÏÍâò°ü¸²¿ÉÒÔÔÚ¸ßЧ»º³å¹è¸º¼«Ç¶ï®Ìå»ýÅòÕ͵Äͬʱ, ÌáÉýï®Àë×ÓÊäÔËÄÜÁ¦, ²¢Ôλ¹¹½¨¸»º¬ÎÞ»ú·ú»¯ÎïµÄ¸ßÎȶ¨ÐÔSEIĤ, ´Ó¶øʵÏÖ¸ÄÉƹ踺¼«Ñ»·Îȶ¨ÐÔµÄÄ¿±ê¡£
1ʵÑéÒªÁì
1.1 ÖÊÁÏÖƱ¸
̼°ü¸²ÄÉÃ×¹è(Si@C)µÄÖƱ¸£º½«0.3 gÉÌÒµ»¯ÄÉÃ×¹è·Û(Á£¾¶20~100 nm, °¢À¶¡ÊÔ¼Á)³¬ÉùÊèÉ¢ÔÚ28 mLÈ¥Àë×ÓË®ºÍÒÒ´¼µÄ»ìÏýÈܼÁ(Ìå»ý±ÈΪ5 : 2)ÖÐ, ¼ÓÈë0.4 mL 3-°±±û»ùÈýÒÒÑõ»ù¹èÍéºó, ½Á°è2 hÐγɾùÔÈÊèÉ¢ÒºA¡£½«0.115 gµÄ4, 4-¶þôÇ»ù¶þ±½ÁòÃѺÍ0.1 gµÄ3-°±»ù·ÓÈÜÓÚ28 mLÈ¥Àë×ÓË®ºÍÒÒ´¼»ìÏýÈܼÁ(Ìå»ý±È5 : 2)ÖÐ, ÐγɾùÏàÈÜÒºB¡£½«ÊèÉ¢ÒºAÓëÈÜÒºB»ìÏý¾ùÔȺó¼ÓÈë0.1 mL°±Ë®, ½Á°è30 minºó¼ÓÈë0.14 mL¼×È©ÈÜÒº(37%~40%), ËùµÃ»ìÏýÈÜÒºÔÚ30 ¡æϺãνÁ°è·´Ó¦12 h¡£·´Ó¦½áÊøºóʹÓÃÒÒ´¼ÓëÈ¥Àë×ÓË®½»ÌæÀëÐÄÏ´µÓ3´Îºó»ñµÃ·ÓÈ©Ê÷Ö¬°ü¸²ÄÉÃ×¹è(Si@AF)¡£½«ÆäÔÚ800 ¡æë²ÆøÖбºÉÕ3 h, »ñµÃ̼°ü¸²ÄÉÃ×¹è(Si@C)¡£
·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹è(Si@C-F)µÄÖƱ¸£º½«100 mg Si@CºÍ200 mg¾ÛÆ«·úÒÒÏ©(PVDF)ÖÃÓÚë²Æø±£»¤µÄ¹Üʽ¯ÖС£Ê¢·ÅPVDFµÄʯӢÖÛλÓÚÆøÁ÷ÉÏÓÎ, Ê¢·ÅSi@CµÄʯӢÖÛλÓÚÆøÁ÷ÏÂÓÎ, ÔÚ600 ¡æ±ºÉÕ3 h, »ñµÃ·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹è(Si@C-F)¡£
1.2 µç³Ø×é×°Óëµç»¯Ñ§ÐÔÄܲâÊÔ
1.2.1 µç³Ø×é×°
×é×°CR2016Ŧ¿Ûµç³Ø½øÐвâÊÔ¡£½«»îÐÔÎïÖÊ¡¢µ¼µçÌ¿ºÚºÍôȼ׻ùÏËάËØÄÆð¤½á¼Á°´7 : 2 : 1µÄÖÊÁ¿±È»ìÏý¾ùÔȺó, ¼ÓÈëÈ¥Àë×ÓË®×÷ΪÈܼÁºÍÊèÉ¢¼Á, ½«»ñµÃµÄ½¬ÁϾùÔÈÍ¿²¼ÔÚͲÉÏ×÷ΪÊÂÇéµç¼«, »îÐÔÎïÖÊÔØÁ¿Îª0.8~1.0 mg¡¤cm-2¡£Ê¹ÓýðÊôï®Æ¬×÷Ϊ¶Ôµç¼«¼°²Î±Èµç¼«¡£µç½âҺΪÈܽâ1.0 mol/L LiTFSI(Ë«Èý·ú¼×»ÇËáõ£ÑÇ°·ï®)Óë2.0% LiNO3µÄDOL/DME(DOLΪ1, 3-¶þÑõÎì»·, DMEΪÒÒ¶þ´¼¶þ¼×ÃÑ, Ìå»ý±È1 : 1)ÈÜÒº¡£ÔÚ³äÂúë²ÆøµÄÊÖÌ×ÏäÖÐ×é×°µç³Ø(Ë®º¬Á¿< 0.1 ¦ÌL/L, Ñõº¬Á¿< 0.1 ¦ÌL/L)¡£
1.2.2 µç³ØÐÔÄܲâÊÔ
ʹÓÃIVIUM Vertex.C.EISµç»¯Ñ§ÊÂÇéÕ¾, ÀûÓÃÑ»··ü°²(Cyclic Voltammetry, CV)·¨ÆÊÎöµç³ØµÄ·´Ó¦»úÀíÓë·´Ó¦¶¯Á¦Ñ§, µçѹÇø¼äΪ0.01~1.5 V, ɨËÙΪ0.05~0.5 mV¡¤s-1; ʹÓõ绯ѧ×迹Æ×(Electrochemical Impedance Spectroscopy, EIS)ÆÊÎöµç¼«¶¯Á¦Ñ§, ²âÊÔƵÂʹæģΪ100 kHz~10 mHz, ÈŶ¯µçѹÕñ·ùΪ5.0 mV¡£Ê¹ÓÃLand CT2001A µç³Ø²âÊÔÒÇ, ÀûÓúãÁ÷³ä·ÅµçÒªÁìÑо¿´¢ï®ÐÔÄÜ, µçѹ´°¿ÚΪ0.01~ 1.5 V (vs. Li/Li+), µçÁ÷ÃܶÈ0.2~5.0 A¡¤g-1¡£
2 ½á¹ûÓëÌÖÂÛ
2.1 ÖÊÁϵÄÐÎò½á¹¹Óë×éÉíÆÊÎö
·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹èÖÊÁϵÄÖƱ¸Àú³ÌÈçͼ1Ëùʾ¡£Ê×ÏÈ, »ùÓÚ·ÓÈ©Ëõ¾Û·´Ó¦ÖƱ¸¾ÛºÏÎï°ü¸²ÄÉÃ×¹è(Si@AF), ²¢ÔÚ¸ßÎÂÏÂת»¯ÎªÎÞ¶¨ÐÎ̼°ü¸²ÄÉÃ×¹è(Si@C)¡£È»ºóÒÔ¾ÛÆ«·úÒÒϩΪ·úÔ´, ÔÚ¸ßÎÂÏÂͨ¹ýÆøÏà·ú»¯ÒªÁìÔÚ¹èÄÉÃ׿ÅÁ£Íⲿ°ü¸²Ì¼²ãÖвôÔÓ·ú¡£Í¼2(a)ΪSi@CºÍSi@C-FÖÊÁϵÄXRDÆ×ͼ, λÓÚ2¦È=28¡ã¡¢47¡ã¡¢56¡ã¡¢69¡ãºÍ76¡ãµÄÑÜÉä·å»®·Ö¶ÔÓ¦ÓÚµ¥¾§¹è(JCPDS 77-2108)µÄ(111)¡¢(220)¡¢(311)¡¢(400)ºÍ(331)¾§Ã档λÓÚ2¦È=25¡ã~26¡ãµÄ¿í·å¹éÊôÓÚ·ÓÈ©Ëõ¾Û²úƷ̼»¯ÐγɵĶ̳ÌÓÐÐò̼½á¹¹¡£¸ßµ¼µçÐÔÓëÓÅÒì½á¹¹ÈáÈÍÐÔµÄ̼°ü¸²²ã¿ÉÒÔÓÐЧ»º½â¹èÖÊÁÏÔÚ³ä·ÅµçÀú³ÌÖзۻ¯Ê§Ð§, ÌáÉýµç¼«µ¼µçÐÔ¡£Í¼2(b)ÊÇSi@CºÍSi@C-FÖÊÁϵÄÀÂüÆ×ͼ, ÔÚ515¡¢947¡¢1350ºÍ1594 cm-1´¦·ºÆðÃ÷ÏÔµÄÎüÊÕ·å¡£ÆäÖÐ, 515ºÍ947 cm-1µÄÎüÊÕ·åÊǾ§Ìå¹èµÄÌØÕ÷·å, »®·ÖÀ´Ô´ÓÚ¹èµÄÒ»½×¹âÉù×ÓÉ¢ÉäºÍ¶þ½×ºáÏò¹âÉù×ÓÉ¢Éä[14]; 1350ºÍ1594 cm-1µÄÎüÊÕ·å»®·Ö¶ÔÓ¦ÓÚ·¼Ïã̼¹¹ÐÍÉìËõÕñ¶¯(GÄ£)ºÍÎÞÐòȱÏÝ̼½á¹¹(DÄ£)¡£Ò»°ã¶øÑÔ, DÄ£ºÍGÄ£µÄÇ¿¶È±È(ID/IG)¿ÉÓÃÒÔȨºâ̼ÖÊÁϵÄȱÏÝˮƽÓëÎÞÐò¶È[15]¡£ÓëSi@CÖÊÁÏ(ID/IG=0.99)Ïà±È, Si@C-FÖÊÁϵÄID/IGÔö´óµ½1.08, ±êÃ÷·ú»¯Àú³Ì¿ÉÔö¼Ó̼°ü¸²²ãµÄȱÏݶÈ, ÓÐÀûÓÚÔÚ½ôÃÜ°ü¸²ÄÉÃ×¹èµÄͬʱ, ÌáÉýï®Àë×ÓÊäÔËÄÜÁ¦¡£
ͼ1 ·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹èÖÊÁϵÄÖƱ¸Àú³ÌʾÒâͼ
ͼ2 Si@CºÍSi@C-FµÄ(a)XRDÆ×ͼ, (b)RamanÆ×ͼ, (c)XPSÈ«Æ×ͼ, ¸ßÇø·Ö(d)F1sºÍ(e)Si2p XPSÆ×ͼ; (f)Si@C-FµÄTGAÇú
XPSÈ«Æ×ͼ±êÃ÷Si@CÖÊÁϺ¬ÓÐO¡¢N¡¢C¡¢SiÔªËØ(ͼ2(c))¡£·ú»¯´¦ÀíºóËù»ñµÄSi@C-FÖÊÁÏÖÐFÔªËØÔ×Ó·ÖÊýԼΪ1.8%¡£¸ßÇø·ÖF1s XPSÆ×ͼ(ͼ2(d))ÖÐ, ÔÚ½áºÏÄÜ686.3ºÍ687.8 eV´¦µÄÁ½¸öÌØÕ÷·å»®·Ö¶ÔÓ¦C-FºÍSi-O-F, ÇÒÒÔC-FΪÖ÷, ±êÃ÷·ú»¯´¦ÀíÔÚÄÉÃ×¹èÍâò°ü¸²µÄÎÞ¶¨ÐÎ̼²ãÖÐÀÖ³ÉÒýÈëÁË·úÔªËØ¡£¸ßÇø·ÖSi2p(ͼ2(e))ÓëF1s XPSÆ×ͼ֤Ã÷SiÔ×ÓÓë̼²ãÖеÄFÔªËØͨ¹ýÐγÉSi-O-F¼ü±¬·¢»¯Ñ§×÷ÓÃ, ÓÐÀûÓÚ̼²ãÔÚ¹èÍâòµÄ½ôÃÜ°ü¸²¡£ÈÈÖØÆÊÎö(TGA)±êÃ÷SiÔÚSi@C-FÖÊÁÏÖеÄÖÊÁ¿·ÖÊýԼΪ85.17%(ͼ2(f))¡£
SEMÆÊÎö±êÃ÷Si@C-FÖÊÁÏÓɳߴç<100 nmµÄÄÉÃ׿ÅÁ£×é³É(ͼ3(a~c))¡£¸ßÎÂ̼»¯¼°ÆøÏà·ú»¯´¦Àíºó, ̼ÖÊÁÏÈÔÈ»¾ùÔÈ°ü¸²ÔÚ¹èÄÉÃ׿ÅÁ£Íâò¡£
ͼ3 Si@C-FÖÊÁϵÄ(a~c)SEMÕÕƬ, (d~f)TEMÕÕƬ¼°Æä(g~i)ÔªËØÂþÑÜÆ×ͼ
TEMÆÊÎö±êÃ÷¹èÄÉÃ׿ÅÁ£±»ÍêÕû¡¢¾ùÔȵذü¸²ÔÚºñ¶ÈԼʮÓàÄÉÃ×µÄ̼²ãÖ®ÖÐ, Ðγɺ˿ǽṹ(ͼ3(d~e))¡£¹èÄÉÃ׿ÅÁ£¾ßÓе¥¾§½á¹¹, ÆäÖÐ0.328 nmµÄ¾§¸ñ¼ä¾à¶ÔÓ¦SiµÄ(111)¾§Ãæ, °ü¸²ÆäÍâµÄ·ú²ôÔÓ̼²ã³ÊÎÞ¶¨Ðνṹ(ͼ3(f))¡£ÔªËØÂþÑÜÆ×ͼ֤Ã÷CºÍSiÔªËØÔÚSi@C-FÖÐÂþÑܾùÔÈ(ͼ3(g~i))¡£
2.2 ÖÊÁϵĵ绯ѧÐÔÄÜ
ͼ4(a, b)ÊÇSi@CºÍSi@C-F¸º¼«ÖÊÁϵÄCVÇúÏß, ɨËÙΪ0.1 mV¡¤s-1, µçѹÇø¼äΪ0.01~1.5 V¡£Ê×´ÎÑ»·ÖÐ, 0.1~0.4 V¹æÄ£µÄÈõ¿í·å¶ÔÓ¦µç½âÒºÆÊÎöÉú³ÉSEIĤµÄ²»¿ÉÄæÀú³Ì; 0.01 V´¦µÄ»¹Ô·å¶ÔÓ¦¾§Ìå¹èͨ¹ýºÏ½ð»¯·´Ó¦Ðγɹè﮺Ͻð(LixSi)µÄÀú³Ì¡£Ëæºó³äµçÀú³ÌÖÐ, 0.32ºÍ0.49 V´¦µÄÁ½¸öÑõ»¯·å¶ÔÓ¦ÓÚLixSiÈ¥ºÏ½ð»¯ÐγɷǾ§¹èµÄÀú³Ì[16]¡£·ú»¯´¦Àí¿ÉÒÔͨ¹ý½á¹¹²ôÔÓÓë¿ÌʴЧӦ, ÔÚSiÖÊÁÏÍâò°ü¸²µÄÎÞ¶¨ÐÎ̼²ãÖÐÒýÈë´ó×ڽṹȱÏÝ, ÐγÉÈýάï®Àë×Ó´«ÊäͨµÀ, ¼ÓËÙï®Àë×ÓÊäÔ˲¢ÔöÇ¿SiÖÊÁϵĵ绯ѧӦ»îÐÔ¡£Òò¶øSi@C-F±ÈÎÞ·ú²ôÔÓµÄSi@C¸º¼«ÔÚ0.49 V´¦ÌåÏÖ³ö¸ü¼âÈñµÄÍÑï®Ñõ»¯·å¡£ÔÚËæºóµÄ·ÅµçÀú³ÌÖÐ, 0.19 V´¦ÐµĻ¹Ô·å¶ÔÓ¦ÓÚÊ״γäµçÀú³ÌÐγɵķǾ§¹èµÄǶï®Àú³Ì[16-17]¡£Ëæ×ÅÑ»·´ÎÊýÔö¼Ó, CVÇúÏßÖÐÑõ»¯·åÓ뻹ԷåµÄλÖò»ÔÙ±ä¸ï, ±êÃ÷Si@CºÍSi@C-F¸º¼«ÖÊÁÏÔÚÊ״γä·Åµçºó×ñÑÀàËƵĺϽ𻯴¢ï®»úÖÆ¡£´ËÀú³ÌÖÐÑõ»¯·åÓ뻹ԷåÖð½¥ÔöÇ¿, ÌåÏÖ³öµä·¶µÄµç¼«»î»¯Àú³Ì¡£
ͼ4 (a, c, e) Si@CºÍ(b, d, f) Si@C-F¸º¼«ÔÚ (a, b) 0.1 mV¡¤s-1ɨËÙϵÄCVÇúÏß, µçÁ÷ÃܶÈΪ(c, d) 0.2ºÍ(e, f) 0.4 A¡¤g-1ʱµÄ³ä·ÅµçÇúÏß
ºãÁ÷³ä·Åµç²âÊÔÖÐ, ½«Si¸º¼«ÖÊÁÏÔڽϵ͵çÁ÷ÃܶÈ(0.2 A¡¤g-1)ÏÂÑ»·»î»¯4´Îºó, ÔÚ0.4 A¡¤g-1µçÁ÷ÃܶÈϲâÊÔÆäÑ»·Îȶ¨ÐÔ¡£Í¼4(c, d)ÊÇSi@CºÍSi@C-F¸º¼«ÔÚ0.2 A¡¤g-1µÄºãµçÁ÷³ä·ÅµçÇúÏß, µçѹ´°¿ÚΪ0.01~1.5 V¡£Ê״ηŵçÀú³ÌÖÐ, ¶þÕß½ÔÔÚ< 0.1 VµçѹÇø¼äÄÚÐÎÉú³¤Æ½Ì¨, ¶ÔÓ¦¾§Ìå¹èºÏ½ð»¯Ç¶ï®Àú³Ì, ´ËÀú³ÌÍùÍùÅãͬ½ÏµÍµÄÊ״οâÂØЧÂÊ¡£Ê״γäµçÀú³ÌÖÐ, ¹è﮺ϽðÍÑï®×ª±äΪǶ﮻ÄܸüµÍµÄ·Ç¾§¹è[18], ʹǶ﮵çλÔÚÊ״γä·ÅµçºóÉý¸ßµ½0.1~0.3 V¡£ÓëSi@CÏà±È, Si@C-F¸º¼«µÄÊ״ηŵç±ÈÈÝÁ¿(2640 mAh¡¤g-1)ÂÔµÍ, µ«Ê״γäµç±ÈÈÝÁ¿(1739.6 mAh¡¤g-1)¸ü¸ß, Ê״οâÂØЧÂÊ(65.9%)±ÈSi@C¸º¼«ÌáÉýÔ¼45.8 %¡£Si@C-F¸º¼«SEIÇøµÄ³ä·ÅµçÇúÏß±ÈSi@C¸ü¶Ì, ±êÃ÷ÍâòÐγÉÁ˸üÎȶ¨µÄSEIĤ¡£ÕâÊÇÓÉÓÚ·ú²ôÔÓ̼²ãÓÐÀûÓÚÔڹ踺¼«ÍâòÓÕµ¼Ðγɺ¬ÎÞ»ú×é·Ö(ÈçLiF)¡¢Îȶ¨ÐÔ¸ü¸ßµÄSEIĤ, ´Ó¶ø½µµÍ²»¿ÉÄæï®ËðʧÒÔ¼°µç½âÒºÏûºÄ[19]¡£
ͼ4(e~f)ÊÇSi@CºÍSi@C-F¸º¼«»î»¯ºó, ÔÚ0.4 A¡¤g-1µçÁ÷ÃܶÈϵijä·ÅµçÇúÏß¡£Ñ»·100´Îºó, Si@C-F¸º¼«ÈԿɼá³Ö1223 mAh¡¤g-1µÄ¸ß±ÈÈÝÁ¿, ÈÝÁ¿¼á³ÖÂÊ>85%(ͼ5(a))¡£ÏàͬÌõ¼þÏÂ, δ¾·ú»¯´¦ÀíµÄSi@C¸º¼«ÔÚ³ä·ÅµçÀú³ÌÖÐÈÝÁ¿Ñ¸ËÙË¥¼õ, Ñ»·100´ÎºóÈÝÁ¿¼á³ÖÂʽöΪ62%, ÏÔʾ³ö·ú²ôÔÓ̼°ü¸²²ã¶ÔÌá¸ß¹è¸º¼«Ñ»·Îȶ¨ÐÔµÄÏÔÖø×÷Óá£Î´¾Ì¼°ü¸²µÄÉÌÒµ»¯ÄÉÃ׹踺¼«ÒòÍÑǶï®Àú³ÌÖо޴óµÄÌå»ýÅòÕÍÓë½á¹¹·Û»¯, Ñ»·10Óà´Îºó¼´¸æʧЧ¡£´ËÀú³ÌÖÐ, Si@C-F¼°Si@C¸º¼«ÓÉÓڻЧӦ, ±ÈÈÝÁ¿ÔÚÇ°10~20´ÎÑ»·ÖÐÖð½¥Ôö´ó¡£ÔÚ0.2~5.0 A¡¤g-1´óµçÁ÷ÃܶÈÏÂ, Si@C-F¸º¼«¿É¼á³Ö1540~580 mAh¡¤g-1µÄ¸ß±ÈÈÝÁ¿, ÌåÏÖ³öÓÅÒìµÄÈÝÁ¿¼á³ÖÂÊ(ͼ5(b))¡£ÔÚ5.0 A¡¤g-1µÄ´óµçÁ÷ÃܶÈÏÂ, ÆäÈÝÁ¿¼á³ÖÂʱÈSi@CÌáÉýÔ¼78%¡£µçÁ÷ÃܶÈÔÙ½µÖÁ0.2 A¡¤g-1ʱ, ±ÈÈÝÁ¿¿É»Ö¸´µ½1450 mAh¡¤g-1, ±êÃ÷ÆäÔڸ߱¶ÂÊ´¢ï®Àú³ÌÖнṹ¸ß¶ÈÎȶ¨¡£ÔÚ0.2 A¡¤g-1µçÁ÷ÃܶÈϳä·ÅµçÑ»·200´Îºó, Si@C-F¸º¼«¿É¼á³Ö>75%µÄ±ÈÈÝÁ¿, ¶øδ¾·ú»¯´¦ÀíµÄSi@C¸º¼«ÈÝÁ¿¼á³ÖÂʽöΪ40%(ͼ5(c))¡£´Ë¸º¼«Ò²ÌåÏÖ³öÓÅÓÚÎÄÏ×±¨µÀÖй踺¼«ÖÊÁϵĴ¢ï®ÐÔÄÜ(±í1)¡£
ͼ5 Si@CºÍSi@C-F¸º¼«(a)ÔÚµçÁ÷ÃܶÈΪ0.4 A¡¤g-1ʱµÄÑ»·ÐÔÄÜ(ÏÈÔÚ0.2 A¡¤g-1µçÁ÷ÃܶÈÏ»4Ȧ); (b)ÔÚµçÁ÷ÃܶÈ0.2~5.0 A¡¤g?1¹æÄ£µÄ±¶ÂÊÐÔÄÜ; (c)ÔÚµçÁ÷ÃܶÈΪ0.2 A¡¤g-1ʱµÄ³¤Ñ»·ÈÝÁ¿¼á³ÖÂÊ
±í1 Si@C-F¸º¼«ÓëÎÄÏ×±¨µÀ¹è¸º¼«µÄµç»¯Ñ§ÐÔÄܱȽÏ
ÖÊÁÏ |
³õʼ CE |
³õʼÈÝÁ¿/£¨mAh¡¤g-1£© |
ÈÝÁ¿ retention |
²ÃÅС£ |
Si@C-F |
65.9% |
2640 |
85% £¨100 ´ÎÑ»·£© |
ÕâÏîÊÂÇé |
ÄÉÃ×¹è/TiN@ |
71% |
2716 |
59.4% £¨110´ÎÑ»·£© |
[20] |
Si@C@RGO |
74.5% |
1474 |
48.9%£¨40 ´ÎÑ»·£© |
[21] |
Si@FA |
65% |
1334 |
68.7%£¨100´ÎÑ»·£© |
[22] |
P-Si@C |
58% |
3460 |
57.5%£¨100 ´ÎÑ»·£© |
[23] |
Si@void@C |
- |
900 |
70%£¨100 ´ÎÑ»·£© |
[24] |
¹è/C@C |
- |
1120 |
80%£¨100 ´ÎÑ»·£© |
[25] |
°ü¸²Ì¼²ãÖеķú²ôÔÓÁ¿¶ÔSi@C-F¸º¼«µÄ´¢ï®ÐÔÄܾßÓÐÏÔÖøÓ°Ïì¡£µ±·ú²ôÔÓÁ¿ÔÚÔ×Ó·ÖÊý1.8%ÒÔÏÂʱ, Si@C-F¸º¼«µÄÑ»·Îȶ¨ÐÔËæ×Å·ú²ôÔÓÁ¿Ôö´ó¶øÏÔÖøÌáÉý(ͼ6), ÕâµÃÒæÓÚ·ú²ôÔÓ¶Ô̼°ü¸²²ãï®Àë×ÓÊäÔËÐÔÖÊÓë¹èÖÊÁÏÍâòSEIĤÎȶ¨ÐÔµÄÔöǿЧӦ¡£·ú²ôÔÓ±ÈÀý¹ý¸ß(>2.7%)ʱ, ̼°ü¸²Si¸º¼«ÖÊÁÏÈÔ¼á³Ö½ÏºÃµÄÑ»·Îȶ¨ÐÔ, µ«±ÈÈÝÁ¿´ó·ù¶ÈϽµ¡£ÕâÊÇÓÉÓÚ¸ßηú»¯Àú³ÌÖÐ, ÆøÏà·úÎïÖÖ¿ÌÊ´µ¼Ö»îÐÔSiËðʧËùÖ¡£·ú²ôÔÓÁ¿ÎªÔ×Ó·ÖÊý1.8%ʱ, Si@C-F¸º¼«ÌåÏÖ³ö×îÓŵÄÑ»·Îȶ¨ÐÔÓë¸ß±ÈÈÝÁ¿¡£
ͼ6 ²î±ð·ú²ôÔÓÁ¿Si@C-F¸º¼«ÔÚ0.4 A¡¤g-1µçÁ÷ÃܶȵÄÑ»·ÐÔÄÜ(ÏÈÔÚ0.2 A¡¤g-1µçÁ÷ÃܶÈÏ»4~10Ȧ)
Si@CºÍSi@C-F¸º¼«µÄEISÆ×ͼÓÉÖиßƵÇøÓòµÄ°ë»¡ÐÎÇúÏߺ͵ÍƵÇøÓòµÄÇãбֱÏß×é³É(ͼ7(a))¡£ÖиßƵ¹æÄ£µÄ°ë»¡ÐÎÇúÏßÓëµçºÉתÒƵç×è(Rct)Ïà¹Ø, µÍƵ¹æÄ£µÄÇãбֱÏßÖ÷ÒªÌåÏÖï®Àë×ÓÀ©É¢µÄWarburg×迹(ZW)[26]¡£³ä·ÅµçÇ°, Si@C-FÓëSi@C¸º¼«µÄRctÏà½ü, µ«Ç°ÕßÓÉÓÚÍâòÁýÕÖ¸ßȱÏݶȵķú²ôÔÓ̼²ã, ZW¸üµÍ¡£³ä·ÅµçÑ»·ºó, Si@C-F¸º¼«µÄRct(5.51 ¦¸)±ÈSi@C¸º¼«(21.97 ¦¸)ÏÔÖø½µµÍ(ͼ7(b)), ͬʱZWÔ¶µÍÓÚºóÕß¡£Õâ±êÃ÷·ú²ôÔÓ̼²ãÓÕµ¼Ðγɵĸ»·úSEI½çÃæĤ¿ÉÒÔÓÐЧÌáÉý½çÃæµçºÉÓëï®Àë×ÓÊäÔËÄÜÁ¦¡£
ͼ7 Si@CºÍSi@C-F¸º¼«ÔÚÑ»·(a)Ç°(b)ºóµÄµç»¯Ñ§×迹Æ×ͼ(µçÁ÷ÃܶÈΪ0.4 A¡¤g-1)
2.3 ³ä·ÅµçºóµÄµç¼«½á¹¹±íÕ÷
³ä·ÅµçÑ»·ºóµÄSEM±íÕ÷(ͼ8(a~c))±êÃ÷, ÓÉÓÚ¹èÔÚǶï®Àú³ÌÖеÄÌå»ýÅòÕÍЧӦÏÔÖø, Si@Cµç¼«µÄºñ¶ÈÔö¼ÓÁË132.3%¡£Õâ²»µ«×è°Àë×ÓÓëµç×Ó´«Êä, Ôö¼Óµç¼«ÄÚ×èÓ뼫»¯, ²¢ÇÒÔì³É¾Þ´óµÄ»úеӦÁ¦, ʹµç¼«ÆÆÁѲ¢Ó뼯Á÷ÌåÊèÉ¢, µ¼ÖÂSi@C¸º¼«ÐÔÄÜ¿ìËÙË¥¼õ(ͼ5(c))¡£ÓëÖ®Ïà±È, Si@C-F¸º¼«³ä·ÅµçÑ»·ºóµç¼«ºñ¶È½öÔö¼ÓÁË26.6%, ²¢¼á³ÖÁËÁ¼ºÃµÄµç¼«½á¹¹Îȶ¨ÐÔ(ͼ8(d~f))¡£Õâ±êÃ÷ÒýÈëµÄ·ú²ôÔÓ̼²ã¿ÉÒÔÔÚ΢¹Û±ê×¼ÉϸßЧ»º³å¹èÖÊÁÏǶ﮵ÄÌå»ýÅòÕÍЧӦ, ´Ó¶ø×Ô϶øÉϵØÔöÇ¿µç¼«ÔÚºê¹Û±ê×¼ÉϵĽṹÎȶ¨ÐÔ¡£
ͼ8 (a)³ä·ÅµçÑ»·ºóµÄSi@CºÍ(d)Si@C-F¸º¼«µÄÍâòSEMÕÕƬ; (b, e)Ñ»·Ç°ºÍ(c, f)Ñ»·ºó(b, c)Si@CºÍ(e, f) Si@C-F¸º¼«½ØÃæµÄSEMÕÕƬ; ³ä·ÅµçÑ»·ºóSi@CºÍSi@C-F¸º¼«ÍâòSEIĤµÄ¸ßÇø·Ö(g)F1s¼°(h)Li1s XPSÆ×ͼ
ÀûÓÃXPSÆÊÎöÁ˳ä·ÅµçÑ»·ºóµÄSi@CºÍSi@C-F¸º¼«ÍâòSEIĤµÄ×é³É(ͼ8(g~h))¡£¸ßÇø·ÖF1s XPSͼÆ×ÖÐ, ÔÚ½áºÏÄÜ684.8¡¢688.3ºÍ689.1eV´¦µÄ½áºÏÄÜ·å»®·Ö¶ÔÓ¦ÓÚLiF¡¢C-F¼üºÍCF2¡£ÏàÓ¦µØ, ¸ßÇø·ÖLi1s XPSͼÆ×ÖÐÒ²±£´æ¶ÔÓ¦ÓÚLiFÎïÖÖµÄÌØÕ÷·å, ±êÃ÷Ôڹ踺¼«ÍâòÐγÉÁ˺¬LiFÎïÖÖµÄSEIĤ¡£ÓëSi@C¸º¼«Ïà±È, Si@C-F¸º¼«ÍâòµÄLiFº¬Á¿¸ü¸ß, ±êÃ÷SEIĤÖеÄLiF³ýÀ´×Ôµç½âÒºÖÐï®ÑÎÆÊÎöÖ®Íâ, ¸ü¶àÀ´Ô´ÓÚ·ú²ôÔÓ̼²ãÖеÄF¡£ÐγɸßÄ£Á¿LiF¿ÉÒÔÓÐЧÔö¼ÓSEIĤµÄ½á¹¹Ç¿¶È, ÒÖÖƹèÖÊÁÏǶï®Ìå»ý±ä¸ï¡£Í¬Ê±, LiFµÄ¿í´ø϶ºÍ¾øÔµÌØÐÔ¿ÉÒÔ¼õСSEIºñ¶È, ½µµÍ³õʼ²»¿ÉÄæï®Ëðʧ¡£LiFÓëSiµÄï®»¯²úÆ·LixSiºÏ½ð¾ßÓнϸߵĽçÃæÄÜ, ¿ÉÒÔ¸üºÃµØÊÊӦ﮻¯¹è¸º¼«ÔÚÑ»·Àú³ÌÖеÄËÜÐÔÐαä, ´Ó¶ø½øÒ»²½ÌáÉýµç¼«µÄÑ»·Îȶ¨ÐÔ[19]¡£
3½áÂÛ
±¾Ñо¿Í¨¹ý¼òÒס¢µÍ¶¾µÄÆøÏà·ú»¯ÒªÁìÖƱ¸ÁË·ú²ôÔÓ̼°ü¸²ÄÉÃ×¹èÖÊÁÏ¡£Ñо¿±êÃ÷, ·ú²ôÔÓ(1.8% F)Ò»·½ÃæÔö¼Ó¹èÍâò̼°ü¸²²ãµÄȱÏݶÈ, ÔÚ½ôÃÜ°ü¸²ÄÉÃ×¹èÒÔÒÖÖÆÆäÌå»ýÅòÕ͵Äͬʱ, Ìṩ¸»ºñµÄï®Àë×ÓÊäÔËͨµÀ; ÁíÒ»·½Ãæ, ÔÚÄÉÃ×¹èÖÊÁÏÍâòÓÕµ¼Ðγɸ»º¬LiFµÄ¸ßÎȶ¨SEIĤ, ½øÒ»²½ÌáÉý¹è¸º¼«µÄÎȶ¨ÐÔÓë¿âÂØЧÂÊ¡£µÃÒæÓÚ´Ë, ·ú²ôÔÓ̼°ü¸²ÄÉÃ׹踺¼«µÄÊ״οâÂØЧÂʸÄÉÆÖÁ65.9%, ÔÚ0.2~5.0 A¡¤g-1µçÁ÷ÃܶÈÏÂ, ÌåÏÖ³ö1540~580 mAh¡¤g-1µÄ¸ß±ÈÈÝÁ¿, Ñ»·200´Îºó, ¿É¼á³Ö>75%µÄ³õʼÈÝÁ¿¡£±¾ÊÂÇéΪÉè¼Æ¹¹Öþ¸ßÈÝÁ¿¡¢¸ßÎȶ¨ÐԵĹ踺¼«ÖÊÁÏÌṩÁËеÄ˼·¡£
²Î¿¼ÎÄÏ×
[1] NIU S S, WANG Z Y, YU M L, et al. MXene¨Cbased electrode with enhanced pseudocapacitance and volumetric capacity for power- type and ultra-long life lithium storage. ACS Nano, 2018, 12(4): 3928.
[2] SU X, WU Q L, LI J C, et al. Silicon-based nanomaterials for lithium-ion batteries: a review. Advanced Energy Materials, 2014, 4(1): 1300882.
[3] GE M Z, CAO C Y, GILL M B, et al. Recent advances in silicon- based electrodes: from fundamental research toward practical applications. Advanced Materials, 2021, 33(16): 2004577.
[4] LI P, ZHAO G Q, ZHENG X B, et al. Recent progress on silicon- based anode materials for practical lithium-ion battery applications. Energy Storage Materials, 2018, 15: 422.
[5] LIU X H, ZHONG L, HUANG S, et al. Size-dependent fracture of silicon nanoparticles during lithiation. ACS Nano, 2012, 6(2): 1522.
[6] LUO W, WANG Y X, CHOU S L, et al. Critical thickness of phenolic resin-based carbon interfacial layer for improving long cycling stability of silicon nanoparticle anodes. Nano Energy, 2016, 27: 255.
[7] DOU F, SHI L Y, CHEN G R, Silicon/carbon composite anode materials for lithium-ion batteries. Electrochemical Energy Reviews, 2019, 2(1): 149.
[8] JIA H P, ZOU L F, GAO P Y, et al. High-performance silicon anodes enabled by nonflammable localized high-concentration electrolytes. Advanced Energy Materials, 2019, 9(31): 1900784.
[9] CHOI S H, KWON T W, COSKUN A, et al. Highly elastic binders integrating polyrotaxanes for silicon microparticle anodes in lithium ion batteries. Science, 2017, 357: 279.
[10] LI Z H, ZHANG Y P, LIU T F, et al. Silicon anode with high initial Coulombic efficiency by modulated trifunctional binder for high areal-capacity lithium-ion batteries. Advanced Energy Materials, 2020, 10(20): 1903110.
[11] XU Z L, CAO K, ABOUALI S, et al. Study of lithiation mechanisms of high performance carbon-coated Si anodes by in-situ microscopy. Energy Storage Materials, 2016, 3: 45.
[12] TEKI R, MONI K D, RAHUL K, et al. Nanostructured silicon anodes for lithium ion rechargeable batteries. Small, 2009, 5(20): 2236.
[13] XIA S X, ZHANG X, LUO L L, et al. Highly stable and ultrahigh- rate Li metal anode enabled by fluorinated carbon fibers. Small, 2021, 17: 2006002.
[14] ZHANG S L, WANG X, HO K S, et al. Raman spectra in a broad frequency region of p-type porous silicon. Journal of Applied Physics, 1994, 76(5): 3016.
[15] HUANG W, WANG Y, LUO G H, et al. 99.9% Purity multi-walled carbon nanotubes by vacuum high-temperature annealing. Carbon, 2003, 41(13): 2585.
[16] MCDOWELL M T, LEE S W, NIX W D, et al. 25th Anniversary article: understanding the lithiation of silicon and other alloying anodes for lithium-ion batteries. Advanced Materials, 2013, 25(36): 4966.
[17] KEY B, MORCRETTE M, TARASCON J M. Pair distribution function analysis and solid state NMR studies of silicon electrodes for lithium ion batteries: understanding the (de)lithiation mechanisms. Journal of American Chemical Society, 2011, 133(3): 503.
[18] GAO H, XIAO L S, PLUMEL I, et al. Parasitic reactions in nanosized silicon anodes for lithium-ion batteries. Nano Letters, 2017, 17(3): 1512. [19] CHEN J, FAN X L, LI Q, et al. Electrolyte design for LiF-rich solid¨Celectrolyte interfaces to enable high-performance microsized alloy anodes for batteries. Nature Energy, 2020, 5(5): 386.
[20] ZHANG P, GAO Y Q, RU Q, et al. Scalable preparation of porous nano-silicon/TiN@carbon anode for lithiumion batteries. Applied Surface Science, 2019, 498: 143829.
[21] SU M R, WAN H F, LIU Y J, et al. Multi-layered carbon coated Si-based composite as anode for lithium-ion batteries. Powder Technology, 2018, 323: 294.
[22] PU J B, QIN J, WANG Y Z, et al. Synthesis of micro-nano sphere structure silicon-carbon composite as anode material for lithium- ion batteries. Chemical Physics Letters, 2022, 806: 140006.
[23] GAO R S, TANG J, YU X L, et al. A sandwich-like silicon-carbon composite prepared by surface-polymerization for rapid lithium-ion storage. Nano Energy, 2020, 70: 104444.
[24] GONG X H, ZHENG Y B, ZHENG J, et al. Yolk-shell silicon/ carbon composites prepared from aluminum-silicon alloy as anode materials for lithium-ion batteries. Ionics, 2021, 27: 1939.
[25] LIA Y R, WANG R Y, ZHANG J W, et al. Sandwich structure of carbon-coated silicon/carbon nanofiber anodes for lithium-ion batteries. Ceramics International, 2019, 45: 16195.
[26] YANG X M AND ROGACH A L. Electrochemical techniques in battery research: a tutorial for nonelectrochemists. Advanced Energy Materials, 2019, 9(25): 1900747.