石墨烯改性LiFePO4/C正极材料的低温电化学性能

作者：江虹1 蔡光兰2 郭瑞松2 韩跃武1

单位：1. 贵州广播电视大学 贵阳 550004 2. 天津大学材料学院 天津 300072

关键词：锂离子电池 正极材料 磷酸铁锂 石墨烯 低温性能

分类号：TM911

出版年,卷(期):页码：2016,44(7):925-930

DOI：10.14062/j.issn.0454-5648.2016.07.02

摘要：

采用悬浮液混合法在热处理温度为400 ℃的条件下制备了石墨烯改性LiFePO4/C复合正极材料。利用X射线衍射分析、扫描电子显微镜、透射电子显微镜等对石墨烯改性LiFePO4/C正极材料的组成、结构和形貌进行了表征，并组装扣式电池，在2.0~4.2 V电压范围下测试了其–10 ℃时的电化学性能。结果表明，5%(质量分数，下同)石墨烯改性的正极粉未样品G5颗粒分布均匀，石墨烯构成了三维导电网络；相比其它组分，样品G5在1C倍率下具有最高的放电容量(115.4 mA·h/g)，循环200次后容量保持率为93.6%；同时，样品G5具有最低的电荷转移阻抗(106.9 )和最高的锂离子扩散系数(7.12×10–11 cm2/s)。

Graphene modified LiFePO4/C cathode material was prepared via a suspension mixing method followed by heat–treatment at 400 ℃. Composition, structure and morphology of graphene modified LiFePO4/C powder were characterized by X–ray diffraction, scanning electron microscope, and transmission electron microscope, respectively. Coin type batteries were assembled using graphene modified LiFePO4/C powders in an argon-filled glove box. The electrochemical properties of the batteries were measured at –10 ℃ in the voltage range of 2.0–4.2 V. It is shown that the 5%(mass fraction) graphene modified cathode powder (sample G5) exhibits the best homogeneous particle size distribution among all the samples and presents a 3D conducting network constituted by graphene. The results also indicate that, compared with other samples, the sample G5 delivers the highest initial discharge capacity (115.4 mA·h/g at 1C) and shows the best cycle performance with 93.6% capacity retention after 200 cycles at 1C. Meanwhile, the battery using cathode powder G5 has the low charge–transfer resistance (106.9 ) and the high diffusion coefficient of lithium ion (7.12×10–11 cm2/s). cialis discount coupons coupons for cialis 2016 cialis 2015 coupon

基金项目：

贵州省省校科技合作计划项目([2014]7003)。

作者简介：

江 虹(1960—)，女，教授。

参考文献：

[1] WANG Y, HE P, ZHOU H. Olivine LiFePO4: development and future[J]. Energy Environ Sci, 2011, 4(3): 805–817. [2] ZAGHIB K, GUERFI A, HOVINGTON P, et al. Review and analysis of nanostructured olivine–based lithium recheargeable batteries: Status and trends[J]. J Power Sources, 2013, 232: 357–369. [3] GOODENOUGH J B, PARK K. The Li–ion rechargeable battery: a perspective[J]. J Am Chem Soc, 2013, 135(4): 1167–1176. [4] PADHI A K, NANJUNDASWAMY K S, and GOODENOUGH J B. Phospho–olivines as positive–electrode materials for rechargeable lithium batteries[J]. J Electrochem Soc, 1997, 144(4): 1188–1194. [5] ZHAO X W, ZHANG G Y, YANG L, et al. A new charging mode of Li–ion batteries with LiFePO4/C composites under low temperature[J]. J Therm Anal Calorim, 2011, 104(2): 561–567. [6] YAO J, WU F, QIU X, et al. Effect of CeO2–coating on the electrochemical performances of LiFePO4/C cathode material[J]. Electrochim Acta, 2011, 56(16): 5587–5592. [7] ZHOU Y, GU C D, ZHOU J P, et al. Effect of carbon coating on low temperature electrochemical performance of LiFePO4/C by using polystyrene sphere as carbon source[J]. Electrochim Acta, 2011, 56(14): 5054–5059. [8] YAO B, DING Z, ZHANG J, et al. Encapsulation of LiFePO4 by in–situ graphitized carbon cage towards enhanced low temperature performance as cathode materials for lithium ion batteries[J]. J Solid State Chem, 2014, 216: 9–12. [9] MA Z, SHAO G, WANG X, et al. Enhanced high rate and low temperature electrochemical properties of LiFePO4/C composites by doping samarium ion[J]. J Solid State Chem, 2013, 17(9): 2409–2416. [10] HARRISON K L, BRIDGES C A, PARANTHAMAN M P, et al. Temperature dependence of aliovalent–vanadium doping in LiFePO4 cathodes[J]. Chem Mater, 2013, 25(5): 768–781. [11] ZHANG H, XU Y, ZHAO C, et al. Effects of carbon coating and metal ions doping on low temperature electrochemical properties of LiFePO4 cathode material[J]. Electrochim Acta, 2012, 83: 341–347. [12] CAI G, GUO R, LIU L, et al. Enhanced low temperature electrochemical performances of LiFePO4/C by surface modification with Ti3SiC2[J]. J Power Sources, 2015, 288: 136–144. [13] LIU H, MIAO C, MENG Y, et al. Effect of graphene nanosheets content on the morphology and electrochemical performance of LiFePO4 particles in lithium ion batteries[J]. Electrochim Acta, 2014, 135: 311–318. [14] DHINDSA K, MANDAL B, BAZZI K, et al. Enhanced electrochemical performance of graphene modified LiFePO4 cathode material for lithium ion batteries[J]. Solid State Ionics, 2013, 253: 94–100. [15] SHI Y, CHOU S, WANG J, et al. Graphene wrapped LiFePO4/C composites as cathode materials for Li–ion batteries with enhanced rate capability[J]. J Mater Chem, 2012, 22(32): 16465–16470. [16] CHOI M, KANG K, KIM H, et al. The effect of titanium in Li3V2(PO4)3/graphene composites as cathode material for high capacity Li–ion batteries[J]. RSC Adv, 2015, 5(7): 4872–4879. [17] LEI X, ZHANG H, CHEN Y, et al. A three–dimensional LiFePO4/carbon nanotubes/graphene composite as a cathode material for lithium–ion batteries with superior high–rate performance[J]. J Alloy Compd, 2015, 626: 280–286. [18] ZHANG B, ZENG T, ZHANG J, et al. Excellent temperature performance of spherical LiFePO4/C composites modified with composite carbon and metal oxides[J]. Sci World J, 2014, 2014: 1–6. [19] KUO P, HSU C, CHIANG H, et al. High rate performance intensified by nanosized LiFePO4 combined with three–dimensional graphene networks[J]. J Nanopart Res, 2013, 15(12): 1966–1974. [20] FATHOLLAHI F, JAVANBAKHT M, OMIDVAR H, et al. Improved electrochemical properties of LiFePO4/graphene cathode nanocomposite prepared by one–step hydrothermal method[J]. J Alloy Compd, 2015, 627: 146–152. [21] LONG Y, SHU Y, MA X, et al. In–situ synthesizing superior high–rate LiFePO4/C nanorods embedded in graphene matrix[J]. Electrochim Acta, 2014, 117: 105–12. [22] JIN Y, YANG C P, RUI X H, et al. V2O3 modified LiFePO4/C composite with improved electrochemical performance[J]. J Power Sources, 2011, 196: 5623–5630. [23] CHO H M, CHOI W S, GO J Y, et al. A study on time–dependent low temperature power performance of a lithium–ion battery[J]. J Power Sources, 2012, 198: 273–280.

服务与反馈：

【文章下载】【加入收藏】