Carbn Letters Vl. 9, N. 3 September 2008 pp. 210-217 Preparatin and Characterizatin f Pitch/Ckes Cmpsite Ande Material fr High Pwer Lithium Secndary Battery Lan Yu 1, Kijung Kim 1, Daeyng Park 2, Myung-S Kim 2, Kab-Il Kim 3 and Yun-S Lim 1, 1 Dept. f Materials Science and Engineering, Myngji University, Gyenggi-d 449-728 Krea 2 Dept. f Chemical Engineering, Myngji University, Gyenggi-d 449-728 Krea 3 Dept. f Electrical Engineering, Myngji University, Gyenggi-d 449-728 Krea e-mail: yslim@mju.ac.kr (Received June 13, 2008; Accepted August, 292008) Abstract Petrleum pitch and cke with wet mixture methd r with dry mixture methd were investigated t develp the cmpsite andic carbn material f high pwer lithium in battery. Ckes cated with pitch were btained by the heat treatment f mixture f ckes and pitch with different weight ratis at 800 ~ 1200 C. The charge and discharge characteristic f the cnsequent cmpsite andic carbn material assembled in batteries was tested. Ckes with wet mixture methd have a smth surface and their capacity changed little with changing temperature and cntent as cmpared t the ckes with dry mixture methd. Althugh the reversible capacities shwed different values by the ande manufacturing methd, the cmpsite ande with the mixture f 20 wt% f petrleum pitch and 80 wt% f cke shwed the higher pwer capability and initial efficiency than the pitch based ande. Hwever, the reversible capacity f the cmpsite ande shwed the reduced value as cmpared with the pitch based ande. Keywrds : Lithium Secndary Battery, Ande, Carbn, Ckes, Pitch rl l v r kp (HEV: Hybrid Electric Vehicle) p rvp p e p erp [1,2]. l pep q p p q p rv s p n q n p rv rvm pm p rv p [1]. rv p l r p Ž pv p p rv p p q rp p r l p v pm p rv l l p l l~l l v p [1,2]. pm p rv p q q l p q q s kr l rp p ˆ q p l ˆ q [3,4]m r ˆ q p [5-7]. ˆ q p sl pm p r vp rn p s j vv p rp r n p ˆ q 6 1 p q p pp lp p n p 372 mah/gp [8-9]. l ˆ r p ˆ p s 372 mah/g p p p n p v rp v l n l p l p n p l v v p [10]. p rvl n rp ˆ q }l lp. }l lp Ž sp l Ž rse v pqp p k v kk pmp p k HEVn p seˆv p [11]. r ˆ q r ˆ rp v, d p p. p l p v l llv rm} ˆ q kp m v p kpv } m p d s v ˆ r ~. p rm} ˆ q lp p n p 372 mah/g j p n p ˆ [12]. v l e v p q vp ˆ l llv le lp p n p k v p [13,14]. d p l l p ˆ v p p v ˆ rl p p k kr p l r r k. dp r n p 200 ~ 250 mah/gp ll lvv k r vp n p [5]. d ll ˆ ˆ p q l pmp p/ˆ pl rp [15]. l l pm p rvp ˆ p q l, rp n
Preparatin and Characterizatin f Pitch/Ckes Cmpsite Ande Material fr High Pwer Lithium Secndary Battery 211 Table 1. Basic Prperties f Petrleum Pitch Sample Petrleum Pitch Sftening Pint ( C) Particle Size Distributin d10 d50 d90 dmax Carbn Yield (%) Slubility f THF (%) Ash (%) 250 0.49 µm 3.08 µm 7.43 µm 12.00 µm 58.05 55.8 0.07 v p d t q r sm q p sq p l p n p ˆ dp l Ž m. v d p v n l r p s m. x k d q l Ž l p r vn p q rs m. Ž p e de p n m. e p d p p n l 12e k ˆ q p. de p n-hexanel l l v kp p r slurry s l n-hexanep r dm e n-hexanel l p 250 Cp tl 1h k s kr eˆ ˆ q p. e de l p rs ˆ q v p l 800 ~ 1200 Cl 1e k l}, planetary mill 325 mesh sieve n l r eˆ p p q n ˆ n m. l l n p p Table 1. n p l rp 250 Cp, pq 3.08 µmp. THF n 55.8%p ash kp 0.07%p ˆ pp v p 1000 Cl 58.05%p. k p sƒ rs ˆ q l l XRD (Philips, U.S.A., CuKα =1.542Å)p l r sp p m, SEM (Hitachi, S-3500N, Japan)p p mp dl p Ž l r p l FE-SEM (Hitachi, S-4800, Japan) p l p q m. TGA (TA Instrument C., TA-Q60, U.S.A.) p N 2 (200 ml/min) l 5 C/minp dm l p m. FT-IR (Bruker C., FT-IR with Raman/NIR Vertex 70 with FT-Raman, U.S.A.)p sp m. l l n rv Žn ˆp yrv, l v v p pn l p vp rs m. p PVDF (plyvinyldene fluride)p n, n NMP (1-methyl-2-pyrrdidinne, Samchun Pure Chemical,, 99.5%) n m p PP(plyprpylene), r v p 1M LiPF 6 mp n 1:1:1 pp EC (ethylene carbnate): EMC (ethyl methyl carbnate): DMC (dimethyl carbnate) r kp n m. p v 93 wt. %l PVDF 7 wt. % r kp NMP ~ p hmgenizer n l 3000~4000 rpmp l d l. d pl p (dctr-blade) p Ž 100 Cp m l 24 h s mp rll press 80 C l 60 µm v k l 2.5 2.5 cm q m. p rs r p seˆ grve bxl m. rs p l k p k p 3 3cm p lithium metalp eˆ cpper meshp n m m p 1ppm p rl glve bxl r k p n l yrv s m. x s rvp r p s l r q (WBCS-3000, Wna Tech, Krea)l s yrv l rr p pn l r e p ee m. r e Cut-ff 0.005 V ~ 2 V v m r C- rate 0.2C re r C-rate 0.2C, 1C, 2C, 3C, 5C v r m. m k p Fig. 1p n as-received m dp XRD m as-received 800, 1000 1200 C l l} XRD ˆ l. Fig. 1-(a)l brad, d rp sharp ˆ p p kp rv vp
212 Lan Yu et al. / Carbn Letters Vl. 9, N. 3 (2008) 210-217 Fig. 1. XRD prfiles f (a) petrleum pitch and ckes, (b) heat-treated petrleum pitch. Fig. 2. FT-IR spectra f (a) petrleum pitch and (b) ckes. l pp, p d l} rp rs d rp rv vp rpp p pl. v l dp r pp p pl. Fig. 1-(b)l l} m 800 Cl 1200 C v v p skv p Intensity v m. p l} m v p r kv p p pl. Fig. 2-(a) l n l FT-IR d p ˆ l. vp rp s v s p p, sp 3050, 1611, 1505, 1052, 872, 811, 750-1l 438 cm ˆ, v s 1p 2955, 2920, 2855 1l 1450 cm ˆ. 3050 cm s tl C-H stretch, 1611 1470 cm mlp p 1 stretching f armatic C = C grup p ˆ. ml 1300 1p 1000 cm s tl inplane C-H bending s ˆ. 900 ~ 700 cm m 1 lp sp ut-f-plane bending f armatic C-H ˆ. 438 cm 1 ut-f-plane bending f armaticp ˆ. 2955, 2920 1p 2855 cm 3 p rp v s ˆ (stretching) ˆ [10]. 800, 1000 1200 Cl 1e j l} l FT-IR p m. 800 Cl l} 1200 Cl l} p p p p. p l} m kvl p v s p l s p t p ppˆ p Ž. Fig. 2-(b)l d
Preparatin and Characterizatin f Pitch/Ckes Cmpsite Ande Material fr High Pwer Lithium Secndary Battery 213 Fig. 3. TGA results f petrleum pitch and ckes. Fig. 4. Discharge characteristics f petrleum pitch at different temperatures. l FT-IR d p ˆ l. As-received ˆp d n k v l} m p ˆ ppp p pp l} l p p ˆ v kk. p d p n pr m l l} v l rs p v s p p ˆp l p k 2 l} l ˆ v k. p v l p TGA p Fig. 3l ˆ l. v l p ˆ pp 1000 Cl k 58.05% r ˆ pl, k p v e l n p tp q. v, 100 gp ne 58 g p n p m. dp n 1000 Cl p k 0.8%p 99.22% ˆ pp e l r l n m. ve gj p p q rs l k l l n m dl rv p p m. e p r vr l} m, de p n- hexanel l v kp p r slurry s l} l p q rs m. l} m 800, 1000 1200 C r l l l ntp rv s s p v s rvp d Fig. 4m Table 2l ˆ l. Fig. 4-(a) (b)l ˆ m p e de
214 Lan Yu et al. / Carbn Letters Vl. 9, N. 3 (2008) 210-217 Table 2. Discharge Characteristics f Petrleum Pitch and Ckes Sample Pwer Capability (%) Initial Efficiency (%) Reversible Capacity (mah/g) DP- 800 C 67 61 399 DP-1000 C 81 75 285 DP-1200 C 65 71 175 WP-800 C 45 59 286 WP-1000 C 90 72 225 WP-1200 C 94 70 210 Ckes 95 80 187 Table 3. Manufactures f Cmpsite Andic Carbn Cde Fabricatin Cnditin fr Cmpsite Andic Carbn D-P80C20 Pitch 80 w/ + Cke 20 w/, 1000 C-1 h heat-treatment D-P50C50 Pitch 50 w/ + Ckes 50 w/, 1000 C-1 h heat-treatment D-P20C80 Pitch 20 w/ + Ckes 80 w/, 1000 C-1 h heat-treatment W-P80C20 Pitch 80 w/ + Ckes 20 w/, 250 C-3 h stabilizatin and 1000 C-1 h heat-treatment W-P50C50 Pitch 50 w/ + Cke 50 w/, 250 C-3 h stabilizatin and 1000 C-1 h heat-treatment W-P20C80 Pitch 20 w/ + Cke 80 w/, 250 C-3 h stabilizatin and 1000 C-1 h heat-treatment rl 800 Cl l} mp p n p ˆ lv p kr p n lvp p pl. l1200 Cl l} mp p kr p kv n p p p pl. l} m 1000 Cp n r p n p kr p ˆ l. p m l l} s q p ˆ ~ ˆ p p l sp q p [16]. el q sq l pmp p p p r l n p v mv r e pm ˆ p l nl p pp k [16]. m v l r p v el q l pp v p kr p v n p [17,18]. d p p n n p kp, p kr p e p rs r l rp pp p pl. de p rs r p l l e d r p n p kp, p kr p 800 Cl l} n rn d p m. Fig. 4-(a) (b) p q l, p ln p l Table 2l ˆ l. e l p l} rs p q p n 800 Cl l} n ln p 399 mah/g n kp, pp 67%m 61% rp n k. 1000 Cl l} n ln p 285 mah/gp t p ˆ lp, pp 81% m 75% ˆ l. de el p l} rs p q p n e el p rs p 1000 Cl rs q q n p ˆ l. 1000 Cl l} p q p n, ers p ln p, ders p p n p m. d r p n p r l ˆ p, ln p n ˆ l p q p n p p l., ln, pp l p q p l} m 1000 C r m. w Table 3l p q p rs s p ˆ l. Table 3p s l p rs p q p l}, planetary mill, 325 p ~ p p q rs m. Fig. 5l d rs p q p SEM ˆ l. SEM vl ˆ p e de p rs p q p ˆ dp ˆ m p kp p Ž l rp ˆ m. de l p rs p q e l p rs p q pqp p Ž p rp ƒr p. Fig. 6p p q p p. d tep Ž p ˆ p. l d pqm l Ž l ppp p pl.
215 Preparatin and Characterizatin f Pitch/Ckes Cmpsite Ande Material fr High Pwer Lithium Secndary Battery Fig. 5. SEM phtgraphs f cke and cmpsite andic carbn. 가역용량은 우수하며, 사이클 안정성은 D-P20C80을 제외하고 는 열등한 특성을 나타내었다. 또한 건식방법으로 1000 C에서 열처리한 피치와 비교해 보면 가역용량은 감소하였고 안정성 은 향상되었음을 확인할 수 있었다. Fig. 7-(b)에는 습식방법에 의한 복합음극재료의 전지 특성인데, 건식방법과 달리 코크스 와의 비교 시 가역용량이 모두 상승하였고, 사이클 안정성도 동등 정도의 경향을 나타내고 있다. 또한 습식방법으로 1000 C 에서 열처리한 피치와 비교해 보면 W-P80C20을 제외하고 가 역용량은 감소하였고 사이클 안정성은 향상되었음을 확인할 수 있었다. Table 4에 복합 음극재료의 출력특성, 초기효율 및 가역용량 을 나타내었다. 건조방식으로 제조한 D-P20C80 복합 음극재 료는 피치나 코크스를 단독으로 사용했을 때보다 우수한 전지 성능을 보임을 확인 할 수 있었다. 또한 다른 복합 음극재료 보다 우수한 전지 성능을 나타냄을 확인 할 수 있었다. 그러 나 습식방법으로 제조한 복합음극재료의 경우, 피치 단독으로 제조된 WP-1000보다는 가역용량이, 코크스보다는 출력특성이 열등한 결과를 나타내었다. 건식방법과 달리 습식방법에 의해 Fig. 6. Crss sectin f cmpsite andic carbn. 3.4. 제조된 복합 음극재료의 전지 특성 Fig. 7에 다양한 질량비로 제조된 복합 음극재료의 전지성 능을 나타내었다. Fig. 7-(a)에는 건식방법에 의해 제조된 복합 음극재료의 결과이다. 복합 음극재료를 코크스와 비교해 보면
216 Lan Yu et al. / Carbn Letters Vl. 9, N. 3 (2008) 210-217 Fig. 7. Discharge characteristics f cmpsite andic carbns. Table 4. Discharge characteristics f petrleum pitch/ckes cmpsites Sample Pwer Capability (%) Initial Efficiency (%) Reversible Capacity (mah/g) D-P80C20 70 76 217 D-P50C50 69 72 196 D-P20C80 92 81 236 DP-1000 C 81 75 285 W-P80C20 90 54 225 W-P50C50 85 67 213 W-P20C80 93 82 194 WP-1000 C 90 72 225 Ckes 95 80 187 Fig. 8. Discharge characteristics f petrleum pitch/ckes cmpsites and petrleum pitch at 1000 C heat treatment.
Preparatin and Characterizatin f Pitch/Ckes Cmpsite Ande Material fr High Pwer Lithium Secndary Battery 217 rs p q l rv p ˆ p d e p rs e n-hexanel p r q p p n m, 250 Cp tl s kr e ˆp f C-O el l} k l s p rp n k pl p Ž. p p l ers l n p r p rp p Ž. e de rl rv p r n p qp rk-n p Fig. 8l ˆ l. Fig. 8p (a)m (b)l p p q rkl p r p n sp l sq p l p n p k pl. lp rs r lr } ˆr sq v k rkp m p l n p d v pl. p l p pr r s l p mp pr rkl p/ˆ l ˆr sq v d p n ll ˆ p q l pmp p/ˆ p p mp p ˆp rl p l m p Ž [19]. l} l rs p q p WP-1000p n dm l p q P-C ƒ p p p p mp ˆ d pl ppp p m. m d l q rs m, pm p rvp p v rn l r r p s k m p p ll. 1. d p q n rvp p tp, l} l p q rs nl 1200 C rn ln p v mp pp r p p pl. p r q p n ders p n l l} 1000 C p l v nl ln p v m p p d m. ders p n l rs p q p p kr e l p rs p q n m. 2. p q rs p, D-P20C80 W-P20C80 p q d r, p ln p v m. e dep rs l ln p p pp, rs l n l} p q pp v mp ln p m. ers p ders n rvr p ˆ l. p rv q l p l l p v lp pl. š x [1] rq lv, pm p rv l, 2007, 6, 10. [2] l, 2 rvl, 2005, 9, 20. [3] Manev, V.; Naidenv, I.; Puresheva, B; Zlatilva, P.; Pisti, G.; J. Pwer Surces 1995,G55, 211. [4] Simn, B.; Flandris, S.; Guerin, K.; Fevrier-Buvier, A.; Teulat, I.; Biensan, P. J.GPwer Surces 1999, 312. [5] Kim, J. S. J. Pwer Surces 2001, 70. [6] Sat, Y.; Tunuma, K.; Takayama, T; Kbayakawa, K.; Kawai, T.; Ykyama, A.G J. Pwer Surses 2001, 97-98, 165. [7] Cnches, A.; Santamaria, R.; Menendez, R.; Alcantara, R.; Lavela, P.; Tirad, J. L.GJ. Pwer Surses 2006, 161, 1324. [8] End, M.; Kim, C.; Nishimura, K.; Fujin, T.; Miyashita, K. Carbn 2000, 38, 183. [9] Yata, S.; Kinshita, H.; Kmri, M.; And, N.; Anekawa, A.; Hashimt, T. ExtendedGAbstracts f 60 th Annual Meeting f the Electrchemical Sciety f Japan, Tky,G Japan, 1993, 2G09. [10] v, ˆ q m pn. m, 2006, 250. [11] v, mpm, md, J. Krean Electrchemical Sc., 2004, 7, 32. [12] Sat, K.; Nguchi, M.; Demachi, A.; Oki, N.; End, M. Science, 1994, 264 556. [13] Mbuchi, A.; Tkumitsu, K.; Fujimt, H.; Kasuh, T. J. Electrchem. Sc., 1995, 142,G1041. [14] Winter, M.; Nvak, P.; Mnnier, A. J. Electrchem. Sc., 1998, 145, 428. [15] Dahn, J. R.; Sileigh, A. K.; Reimers, J. N.; Zhng, Q.; Way, B. M. ElectrchemicaGActa, 1993, 38, 1179. [16] Mchida, I.; Ku, C. H.; Yn, S. H.; Krai, Y. J. Pwer Surces, 1998, 75, 214. [17] Zheng, T.; Liu, Y.; Fuller, S.; Tseng, U.; Sackn, V.; Dahn, J. R. J. Electrchem Sc.,G1995, 142, 2851. [18] Takami, N.; Sath, A.; T. Ohsaki, T. Ekectrchim Acta, 1997, 42, 2537. [19] Dahn. J. R.; Sileigh, A. K.; Reimers, J. N.; Zhng, Q.; Way, B. M. ElectrchimicaGActa, 1993, 38, 1179.