669

Size: px

Start display at page:

Download "669"

钜杭
5 years ago
Views:

1 April (Wuli Huaxue Xuebao) Acta Phys -Chim Sin 2014, 30 (4), [Article] doi: /PKUWHXB wwwwhxbpkueducn / 5 V LiNi 05 Mn 15 O 4 1 1,* 2,3 3 ( 1, ; 2, ; 3 ( ), ) : LiNi 05Mn 15O 4 (NH 4) 2CO 3 (NH 4) 2C 2O 4,,, LiNi 05Mn 15O 4, LiNi 05Mn 15O 4, 1414 mah g -1 03C 1C 3C mah g -1 (963%) 1286 mah g -1 (944%) 1139 mah g -1 (911%), LiNi 05Mn 15O 4 40 V,,, LiNi 05Mn 15O 4, 6486 mwh g mw g -1 : ; ; / ; ; : O646 Preparation and Electrochemical Performance of 5 V LiNi 05 Mn 15 O 4 Cathode Material by the Composite Co-Precipitation Method for High Energy/High Power Lithium Ion Secondary Batteries ZHU Zhi 1 QI Lu 1,* LI Wei 2,3 LIAO Xi-Ying 3 ( 1 College of Chemistry and Molecular Engineering, Peking University, Beijing , P R China; 2 School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing ; 3 SYN Chemicals & Technology (Beijing) Co Ltd, Beijing , P R China) Abstract: This research developed a novel composite co-precipitation method to prepare high performance LiNi 05Mn 15O 4 based on a traditional solid-state method Ammonium oxalate/ammonium carbonate was used as a composite precipitator to deposit Ni/Mn ions Combined with a facile hydrothermal treatment, stoichiometric LiNi 05Mn 15O 4 was obtained with a pure spinel structure and spherical hierarchical morphology Electrochemical measurements indicate that the as-prepared LiNi 05Mn 15O 4 delivers a high capacity of 1414 mah g -1 and after 200 cycles under 03C, 1C, and 3C, the materials retained their capacities up to 963%, 944%, and 911%, respectively Additionally, the capacity upon exposure to a low voltage of 40 V was efficiently eliminated by heat treatment and by a particular cooling process Furthermore, the LiNi 05Mn 15O 4 materials with high energy and high power performances of 6486 mwh g -1 and 7000 mw g -1 were obtained because of different cation ordering Key Words: Lithium ion battery; Spinel lithium nickel magnesium oxide; High energy/ high power; Co-precipitation method; Spherical hierarchical morphology Received: November 19, 2013; Revised: January 26, 2014; Published on Web: February 10, 2014 Corresponding author gilu297542@pkueducn; Tel: Editorial office of Acta Physico-Chimica Sinica

2 670 Acta Phys -Chim Sin 2014 Vol30 1 LiNi 05Mn 15O 4 5,6, ,, LiNi 05Mn 15O 4,,, 15, mah g -1, 6, 4 V ( Li ), 17 LiFePO V, LiCoO 2 LiNi 05Mn 15O 4 LiMn 2O V LiNi 05Mn 15O V,,, LiNi 05Mn 15O 4,,, 400 V LiNi 05Mn 15O 4,,, LiFePO 4 135, LiMn 2O 4 110, LiNi 05Mn 15O , 21 LiNi 05Mn 15O 4 LiNi 05Mn 15O Wh kg -1, 3C, LiOH H 2O (, 2000 W kg -1 LiNi 05Mn 15O 4 LiMn 2O 4 MnO 2 (, ),, LiMn 2O 4 2 h, Ni 2+/4+,, 600 C 47 V 2-4 5h 1-2 h Ni LiNi 05Mn 15O 4, C 12 h, T- LiNi 05Mn 15O 4 LNMO : 106:050:150 ) Ni(OH) 2 (, ) ( ): 1:3 NiSO 4 (, ) MnSO 4 (, ), Ni Mn 1-3 mol L mol L -1 (NH 4) 2CO 3(, ) (NH4) 2C 2O 4(, ) (NH 4) 2CO 3 (NH 4) 2C 2O 4, 4% (NH 4) 2CO 3, 10 min 96% (NH 4) 2C 2O 4 1 Fig 1 Charging/discharging curves of common materials C, ph in Li-ion battery versa Li metal as anode, ph

3 No4 : / 5 V LiNi 05Mn 15O H 2SO MnO C,,,,, 120 C 5 h,,, 120 C 1, C 6-8 h : (1) (05-08 C min -1 ) 650 C, N0-LNMO; (2) (25-30 C min -1 ), N1- LNMO; (3) N1- LNMO 2a 670 C, 40 h N2-LNMO 181%, 167% 22 T-LNMO ( (SEM) (JEOL, XRD ) JSM-5600LV, Japan), 20 kv,, X (XRD) (Rigaku Muti- Flex Diffractometer, D/max-2500, Japan), 780 C, Cu, 20 kv, 4mA, 10 -, 90, (TGA) (Setaram Labsys, France), 2b N-LNMO - 10 ( ) min -1 (TGA-DSC), 23 R2032,, TGA 86% (w, ) 8% : C ( + ) 6% PVDF, C 1 mol L -1 LiPF 6 1: TG, 500 C 1:1 (EC), (DMC), DSC (EMC) Li 500 C Li-Ni-Mn LAND CT2001A ( ), 500 C, LiNi 05Mn 15O 4, V 3 31 ), Li Ni Mn ( C) Li 2NiMn 3 5C 2O 4, LiOH, LiNi 05Mn 15O 4, 19 2a T-LNMO LiOH Ni(OH) 2 MnO 2 TGA LiNi 05Mn 15O 4,, 850 C LiNi 05Mn 15O 4 LiNi 05Mn 15O 4, 2b 18 (, N-LNMO : NiSO 4+3MnSO 4+4(NH 4) 2C 2O 4, 1 18 NiMn 3(C 2O 4) 4+4(NH 4) 2SO 4 (1) 2a, , NiMn 3(C 2O 4) 4+2LiOH LiOH H 2O 2LiNi 05Mn 15(OH)(C 2O 4) 2 (2) 270 C, Ni(OH) 2 LiOH LiNi 05Mn 15(OH)(C 2O 4) 2+175O 2

4 672 Acta Phys -Chim Sin 2014 Vol30, 3a C LiNi 05Mn 15O 4(T- LNMO), T- LNMO, (311) (400) 1000 C, 900 C,, LiNi 05Mn 15O 4 (N0-LNMO) XRD 3b, 500 C, 800 C, LiNi 05Mn 15O 4,, XRD ( 3b), (311) 2 (a) (b) LiNi 05Mn 15O 4 TG-DSC Fig 2 Thermogravimetry-differential scanning calorimetry (TG-DSC) curves of preparing LiNi 05Mn 15O 4 via (a) traditional solid state method and (b) novel co-precipitation method LiNi 05Mn 15O 4+4CO 2+05H 2O (3) 2b, 240 C 4149%, (3) 4140%, Li Ni Mn, LiNi 05Mn 15O 4 32 X 1 LiNi 05Mn 15O 4 18 Table 1 Possible reactions during sintering the raw mixture in traditional solid-state method 18 T/ C Reaction LiOH H2O LiOH+H2O Ni(OH)2 NiO+H2O LiOH(s) LiOH(l) Li2O+H2O Li2O+NiO Li2NiO2 4MnO2 2Mn2O3+O2 Li2O+NiO+15Mn2O3+075O2 2LiNi05Mn15O4 3 (a) (T-LNMO) (b) (N0-LNMO LiNi 05Mn 15O 4 XRD Fig 3 X-ray diffraction (XRD) patterns of LiNi 05Mn 15O 4 preparing via (a) traditional solid state method and (b) novel composite co-precipitation method

No4 朱智等: 新型复合共沉淀法制备高能量/高功率型锂离子二次电池用 5 V 正极材料 LiNi05Mn15O4 及其电化学性能 673 (400)峰强的比值常用来评定材料中阳离子的混排度(γ) 在 LiNi05Mn15O4 中, γ表示材料中 8a 位置的 Li 离子和 16d 位置的 Mn 或 Ni 离子的混排程度通常γ 越大, 两者峰强的比值 I(311)/I(400) 也越大,

5 No4 朱智等: 新型复合共沉淀法制备高能量/高功率型锂离子二次电池用 5 V 正极材料 LiNi05Mn15O4 及其电化学性能 673 (400)峰强的比值常用来评定材料中阳离子的混排度(γ) 在 LiNi05Mn15O4 中, γ表示材料中 8a 位置的 Li 离子和 16d 位置的 Mn 或 Ni 离子的混排程度通常γ 越大, 两者峰强的比值 I(311)/I(400) 也越大, 材料的电化学性能也会降低从图 3 中可以看出, 新共沉淀法制备的 N0-LNMO(084)的 I(311)/I(400) 值明显低于传统固相法制备的 T-LNMO(093) 这是由于在材料制备过程中, 新方法均对混合反应物进行了化学预处理, 使元素得到了原子级别的充分混合, 从而较容易生成元素排布规律的纯相尖晶石 LiNi05Mn15O4因此可以预测, N0-LNMO 的电化学性能将优于传统固相法制备的 T-LNMO 33 材料颗粒表面形貌 SEM 分析为了更好地阐述新共沉淀法制备 LiNi05Mn15O4 的过程, 本研究中用 SEM 表征了新方法中预反应物中间产物以及最终产物的颗粒表面形貌图 4 为新共沉淀法制备 LiNi05Mn15O4 过程中, 从预反应物到最终产物的 SEM 照片如图 4a 所示, 通过控制共沉淀过程中的各项条件(如水浴温度溶液的浓度和 ph 等), 可以得到均匀的球形沉淀颗粒, 粒径约为 6 μm 实验发现, 使用(NH4)2CO3 沉淀剂更易于得到这种球形颗粒20 因此在滴加沉淀剂时, 先使用少量的(NH4)2CO3 沉淀剂待母液出现明显浑浊时, 溶液中已有大量球形晶核形成, 这时再滴加 (NH4)2C2O4 沉淀剂需要强调的是, (NH4)2CO3 沉淀剂的使用量要控制在总沉淀剂的 10%以内, 否则过多的碳酸盐沉淀物会影响前驱物的组成与 LiOH 饱和溶液水热反应后的前驱物颗粒的电镜照片如图 4b 所示可以发现颗粒的形貌基本未变, 只是表面附有大量 LiOH 颗粒在传统方法制备 LiNi05Mn15O4 时, LiOH 往往是通过机械球磨的方式和 Ni-Mn 化合物混合这样的传统混合方法不仅不能使各金属离子达到原子级别的混合, 还会破坏原前驱物颗粒的形貌而本方法中采用水热法, 当 Ni/ Mn 草酸盐颗粒与饱和 LiOH 溶液发生水热反应时, 大部分 LiOH 会向球形颗粒内部扩散, Li 离子与 Mn/ Ni 离子充分混合当溶液被蒸干时, 溶液中残留的少许 LiOH 会吸附在球形颗粒的表面, 如图 4b 所示这种水热处理过程不仅让各离子在原子级别充分混合, 而且不会破坏 Ni-Mn 颗粒的原始形貌图 4(c, d)为将上述前驱物分别在 500 和 800 C 高温反应后得到的颗粒 SEM 照片经过 500 C 高温反应后的颗粒表面变得光滑, 如图 4c 所示这表明粘附在球形颗粒表面的 LiOH 已经分解且 Li 离子均已扩散到球形颗粒内部, 与 Ni 和 Mn 发生了反应结合 TG 和 XRD 结果可以推断, 此时得到的材料为 LiNi-Mn 的复合氧化物, 且尖晶石结构已初步形成, 但结晶度较低图 4d 为在 800 C 高温反应后得到的材料从图 4d 可以看出, 生成的 LiNi05Mn15O4 仍为球形, 但具有明显的次级结构特征这些球形的粒径保持不变, 仍为 5-6 μm, 但这些颗粒由纳米级或亚微米级一次颗粒组成, 一次颗粒具有八面体形貌可以推测, 该次级结构一方面有利于电解液充分浸润正极从而提高电池的倍率性能; 另一方面, 可以提高材料的振实密度进而提高材料的能量密度20 34 红外表征尖晶石材料内部原子排列的有序性结构根据过渡金属离子 Ni 和 Mn 的排布是否有序, LiMn15Ni05O4 有 P4332 和 Fd3m 两种结构在 P4332 简单立方结构中, Li 离子位于 4a 位置, Ni 和 Mn 离子分别位于 12d 和 4c 而在 Fd3m 面心立方结构中, Li 离子位于 8a 位置, Ni 和 Mn 离子则无序地排列在 16d 八面体位置由于在 P4332 结构中, Ni Mn 离子的有序排布而产生的超晶格结构对 X 射线的衍射强度很弱, 因此很难通过粉末 X 射线衍射来区分 LiMn15Ni05O4 属于何种结构于是本文采用傅里叶变换红外(FTIR)光谱来分析 LiMn15Ni05O4 的结构图 4 新型共沉淀法制备 LiNi05Mn15O4 的 SEM 图 Fig 4 Scanning electron microscopy (SEM) images of the particles in the novel preparation process (a) carbonate/oxalate composite sediments; (b) precursor; (c) intermediate product; (d) final LiNi05Mn15O4 图 5 为新共沉淀法中通过三种不同冷却处理所得到的 LiMn15Ni05O4 材料 (N0- LNMO N1- LNMO N2-LNMO)的 FTIR 图谱图中位于 620 cm-1 处的较强吸收峰对应着尖晶石中 MnO6(A1g)八面体 Mn O

6 674 Acta Phys -Chim Sin 2014 Vol30 5 LiMn 15Ni 05O 4 FTIR Fig5 Fourier transform infrared (FTIR) spectra of the LiNi 05Mn 15O 4 by three different cooling processes 35 ; 510 cm -1 LiNi 05Mn 15O 4, Ni 2+ O ; cm -1 Li T (3)2g, Ni Mn 6 LiNi 05Mn 15O 4 6 : Ni Mn, (a-c), LiNi 05Mn 15O 4, cm -1 T (3)2g 47 V, 40 V P4 332 Fd3m, Ni Mn, N1-LNMO, T (3)2g, N1-LNMO Ni/Mn Fd3m, N2- LNMO, T (3)2g, N2-LNMO Ni/Mn, P4 332 N0- LNMO T (3)2g, P4 332 Fd3m, LiMn 15Ni 05O 4, P4 332 Fd3m,, LiMn 15Ni 05O 4, 47 V Ni 2+/4+ 5, cm -1, 40 V Mn 3+/4+ T (3)2g, 6(a, b), 750 C(T- Fig 6 6 (a, b) (c, d) LiNi 05Mn 15O 4 (a-c) (d) Charging/discharging curves (a-c) and cycling performance (d) of LiNi 05Mn 15O 4 prepared by traditional solid (a, b) state and novel co-precipitation (c, d) methods

7 No4 : / 5 V LiNi 05Mn 15O LNMO-750) 900 C(T-LNMO-900), Mn 3+, LiNi 05Mn 15O mah g -1 03C 300, 34 N1-LNMO 698% 744%, N2-LNMO, 900 C LiNi 05Mn 15O 4 Fd3m, P C, N1-LNMO N2-LNMO N0-LNMO 6c 03 C 1C 3C, N0- LNMO mah g -1, N0-LNMO 47V Mn 4 + 5C, N2-, 983% N0-LNMO 6d, 03C 1C 3C 1033 mah g -1 10C 200, N0-LNMO 1360 mah g -1 (963%), 1286 mah g - 1 (944%), 1139 mah g - 1 (911%), N2-LNMO, mah g -1, 7b N1-LNMO 05C 10C LiNi 05Mn 15O 4, 05C, 40 V,, 7a, 05C, N2-LNMO 1414 mah g -1, 4 7V, Mn 3 + LNMO (<46 V),, N2-LNMO 44 V, 585 mah g -1 N1- LNMO N2- LNMO, 1356 Fd3m LiNi 05Mn 15O 4 mah g -1, 40 V, 7 LiNi 05Mn 15O 4 ((a)n2-lnmo ( b)n1-lnmo) (c) (d) Fig7 Discharging curves of LiNi 05Mn 15O 4 materials ((a) N2-LNMO, ( b) N1-LNMO), (c) rates performance, and (d) power-energy releasing curves

8 676 Acta Phys -Chim Sin 2014 Vol30 N1-LNMO N2-LNMO 5C 10C, N1-LNMO mah g -1, V N2-LNMO 7c N1-LNMO N2-LNMO, 05C, N2-LNMO, N1-LNMO 5 mah g -1 N2-LNMO Mn 3+, 5C 10C, N1- LNMO N2-LNMO, N1-LNMO, N1-LNMO N2-LNMO, 7d LiNi 05Mn 15O 4 7d, 400 mw g -1, N2-LNMO 6486 mwh g -1, N2-LNMO 5964 mwh g - 1 ; 7000 mw g -1, N2-LNMO 2902 mwh g -1, N1-LNMO 4407 mwh g - 1, N1-LNMO, ; N2-LNMO, 4 electacta LiNi 05Mn 15O 4, LiNi 05Mn 15O mah g -1, 40 V, jpowsour LiNi 05Mn 15O 4, LiNi 05Mn 15O mah g -1, 47 V 983% 03C, 1C 3C mah g -1 (963%), 1286 mah g -1 (944%) 1139 mah g -1 (911%) LiNi 05Mn 15O 4, References (1) Qi, L Lithium Ion Secondary Battery for Electronica Vehicle, 2nd ed; Science Press: Beijing, 2013; pp 49 mwh g -1, [ ( ) :, 2013: 49] (2) Terada, Y;Yasaka, K; Nishikawa, F; Konishi, T;Yoshio, M; Nakai, I J Solid-State Chem 2001, 156, 286 doi: / jssc (3) Song, M Y; Ahn, D S Solid State Ionics 1998, 112 (1-2), 21 doi: /S (98) (4) Kim, J H; Myung, S T; Sun, Y K Electrochim Acta 2004, 49, 219 doi: /jelectacta (5) Santhanam, R; Rambabu, B J Power Sources 2010, 195, 5442 doi: /jjpowsour (6) Hagh, N M; Amatucci, G G J Power Sources 2010, 195, 5005 (7) Liu, G Q; Wang, Y J; Qi, L; Li, W; Chen, H Electrochim Acta 2005, 50 (9), 1965 (8) Hwang, B J; Wu, Y W; Venkateswarlu, M; Cheng, M Y; Santhanam, R J Power Sources 2009, 193, 828 doi: /j jpowsour (9) Lee, Y S; Sun, Y K; Ota, S; Miyashita, T; Yoshio, M Electrochem Commun 2002, 4, 989 doi: /S (02) (10) Fan Y; Wang, J; Ye, X; Zhang, J Mater Chem Phys 2007, 103, 19 doi: /jmatchemphys (11) Sun, Y K; Oh, S W; Yoon, C S; Bang, H J; Prakash, J J Power Sources 2006, 161, 19 doi: /j jpowsour (12) Fang, X; Ding, N; Feng, X Y; Lu, Y; Chen, C H Electrochim Acta 2009, 54, 7471 doi: /j (13) Chen, Z; Zhu, H; Ji, S; Linkov, V; Zhang, J; Zhu, W J Power Sources 2009, 189, 507 doi: /j jpowsour (14) Fang, H S; Wang, Z X; Li, X H; Guo, H J; Peng, W J J Power Sources 2006, 153, 174 doi: /j (15) Takahashi, K; Saitoh, M; Sano, M; Fujita, M; Kifune, K J Electrochem Soc 2004, 151 (1), A173 (16) Wu, S; Kim, S J Power Sources 2002, 109, 53 doi: / S (02) (17) Park, S B; Eom, W S; Cho, W I; Jang, H J Power Sources 2006, 159, 679 doi: /jjpowsour (18) Zhu, Z; Yan, H; Zhang, D; Li, W; Qi, L J Power Sources 2013, 224, 13 doi: /jjpowsour (19) Zhu, Z; Qi, L; Zhang, D; Yu, H Y Electrochim Acta 2014, 115, 290 doi: /jelectacta (20) Zhu, Z; Zhang, D; Yan, H; Li, W; Qi, L J Mater Chem A 2013, 1, 5492 doi: /c3ta10980a

Sn 1 3 Sn-Co Sn XRD X pert PRO X 1 Panalytical Cu Kα kv 30 ma 20 ~ s LEO1530 LEO SEM 1 4 Sn-Co 2025 Sn-Co 1 mol L m

Sn 1 3 Sn-Co Sn XRD X pert PRO X 1 Panalytical Cu Kα kv 30 ma 20 ~ s LEO1530 LEO SEM 1 4 Sn-Co 2025 Sn-Co 1 mol L m 16 2 Vol 16 No 2 2010 5 ELECTROCHEMISTRY May 2010 1006-3471 2010 02-0161-07 Sn-Co 1 1* 1 2* 1 2 361005 Sn-Co X- XRD SEM SnCo CoSn 2 Sn SnCo SnCo 636 3 mah /g 528 7 mah /g 83 1% 70 529 5 mah g - 1 82 6%