以荷叶制备多级孔碳硫复合正极材料及性能研究

doi:10.15541/jim20150373

摘要/Abstract

摘要：

以荷叶为原料, 采用多阶炭化的方法, 得到高比表面积(572.1 m²/g)和存在大量多级孔尤其微孔(平均孔径3.31 nm)结构居多的炭骨架, 继而用高能球磨法及熔融法与单质硫进行复合制备出不同含硫量(48wt%, 62wt%, 71wt%)碳/硫复合材料。通过XRD、FESEM、EDS和TG对材料结构和形貌进行表征, 结果表明硫被均匀固定在多孔碳材料的类石墨烯层状结构和类微米棒结构中。充放电测试表明, 62wt%含硫量的复合正极材料性能表现最佳, 在0.1C, 1.2~2.8 V范围内充放电, 首次放电比容量达1246 mAh/g, 100次循环后依旧保持在600 mAh/g, 制备出的复合正极材料对多硫化物的“穿梭效应”起到了抑制作用。

关键词: 锂硫电池, 多阶炭化, 多级孔, 荷叶

Abstract:

The carbon skeleton with high specific surface (572.1 m²/g) and large number of hierarchical pores especially micro-pores (average pore size at 3.2 nm) was obtained from common lotus-leaves by using multistage carbonization method. Ball milling and melting method were used to synthesize different S contents (48wt%/ 62wt%/71wt%) carbon/sulfur composite materials. XRD, FESEM, EDS, and TG were employed to analyze structure and morphology of the samples. The result indicated that element sulfur was uniformly accommodated in the skeletons which were composed by graphene-like layered structure and micrometer sticks. Charge/discharge tests at current density of 0.1C in the voltage range of 1.2-2.8 V showed that the initial discharge specific capacity of the carbon/sulfur composite (62wt%) reached 1246 mAh/g, and its capacity still remained 600 mAh/g even after 100 charge/discharge cycles. The results prove that the obtain composites can suppress the “shuttle effect” of polysulfide species effectively.

Key words: lithium sulfur battery, multistage carbonization, hierarchical porous pores, lotus-leaves

中图分类号:

TM912

杨书廷, 闫崇, 曹朝霞, 史梦姣, 李艳蕾, 尹艳红. 以荷叶制备多级孔碳硫复合正极材料及性能研究[J]. 无机材料学报, 2016, 31(2): 135-140.

YANG Shu-Ting, YAN Chong, CAO Zhao-Xia, SHI Meng-Jiao, LI Yan-Lei, YIN Yan-Hong. Preparation of Hierarchical Porous Carbon/Sulfur Composite Based on Lotus-leaves and Its Property for Li-S Batteries[J]. Journal of Inorganic Materials, 2016, 31(2): 135-140.

图/表 10

图1 样品的XRD图谱

Fig. 1 XRD patterns of samples (a) Sulfur; (b) Hierarchical porous carbon; (c) C/S composites

图2 不同硫含量的复合材料热重曲线图

Fig. 2 TGA profiles of C/S composite with different sulfur contents (a) 48wt% S; (b) 62wt% S; (c) 71wt% S

图3 多级孔碳材料(a)和碳/硫复合材料(b)的吸脱附等温曲线及孔径分布

Fig. 3 Adsorption-desorption isothermal and inset pore size distribution curves of carbon (a) and carbon/sulfur composite materials (b)

表1 多孔碳材料和碳/硫复合材料的孔结构参数

Table 1 Pore parameters derived from N2 adsorption data

Samples	Surface area /(m²·g^-1)	Pore diameter /nm	Pore volume /(cm³·g^-1)
C	572.1	3.31	0.52
C/S	11.5	0.04	0.08

图4 多级孔碳材料的FESEM照片(a, b, c, d)及能谱分析图(e, f)

Fig. 4 FESEM images of hierarchical porous carbon (a~d) and EDS analysis (e, f) (a) Morphology before acid treatment; (b) Morphology after acid treatment; (c) Similar graphene layered structure; (d) Similar micrometer sticks; (e) Qualitative analysis of EDS; (f) Quantitative analysis of EDS

表2 碳/硫复合材料的EDS定量分析表

Table 2 EDS quantitative analysis of C/S composite

Element	wt%	at%
Sulfur16 K-series	67.55	43.81
Carbon6 K-series	32.45	56.19
Chlorine17 K-series	0.00	0.00

图5 不同含硫量(48wt%、62wt%、71wt%)的碳/硫复合材料循环充放电性能

Fig. 5 Cycling performance of C/S composite with different contents of sulfur (a: 62wt% S; b: 48wt% S; c:71wt% S)

图6 62wt%含硫量复合材料的第1圈、第5圈和第20圈的充放电曲线

Fig. 6 Galvanostatic charge-discharge curves of the 1st, 5th, 20th charge-discharge process for C/S composite with 62wt% sulfur

图7 62wt%含硫量复合材料的倍率性能图

Fig. 7 Rate performance of C/S (62wt%) composite

图8 62wt%含硫量复合材料在扫速为0.05mV/s的循环伏安曲线

Fig. 8 CV profiles of C/S composite with 62wt% sulfur at scanning rate of 0.05 mV/s

参考文献 17

[1]	GWON H, HONG J, KIM H, et al.Recent progress on flexible lithium rechargeable batteries.Energy & Environmental Science, 2014, 7(2): 538-551.
[2]	RUI XU, LU JUN, AMINEK. Progress in mechanistic understanding and characterization techniques of Li-S batteries.Advanced Energy Materials, 2015, doi:10.1002/aenm.201500408.
[3]	YIN YA-XIA, XIN SEN, GUO YU-GUO, et al.Lithium-sulfur batteries: electrochemistry, materials, and prospects.Angew Chem. Int. Ed. Engl., 2013, 52(50): 13186-13200.
[4]	MANTHIRAM A, FU YONG-ZHU, CHUNG SHENG-HENG, et al.Rechargeable lithium-sulfur batteries.Chemical Review, 2014, 114(23): 11751-11787.
[5]	ZHANG B, QIN X, LI G.R, et al. Enhancement of long stability of sulfur cathode by encapsulating sulfur into micropores of carbon spheres.Energy & Environmental Science, 2010, 3(10): 1531-1537.
[6]	ZHENG GUANG-YUAN, YANG YUAN, CUI YI, et al.Hollow carbon nanofiber-encapsulated sulfur cathodes for high specific capacity rechargeable lithium batteries.Nano Letters, 2011, 11(10): 4462-4467.
[7]	ZHANG SONG-TAO, ZHENG MING-BO, LIN ZI-XIA, et al.Activated carbon with ultrahigh specific surface area synthesized from natural plant material for lithium-sulfur batteries.J. Mater. Chem. A, 2014, 2(38): 15889-15896.
[8]	ZHAO SHENG-RONG, LI CHENG-MING, WANG WEI-KUN, et al.A novel porous nanocomposite of sulfur/carbon obtained from fish scales for lithium-sulfur batteries.J. Mater. Chem. A, 2013, 1(10): 3334-3339.
[9]	YE HUAN, YIN YA-XIA, GUO YU-GUO, et al.Tuning the porous structure of carbon hosts for loading sulfur toward long lifespan cathode materials for Li-S batteries.J. Mater. Chem. A, 2013, 1(22): 6602-6608.
[10]	WU YI-HAN, XU CHUN-MEI, GUO JIN-XIN, et al.Enhanced electrochemical performance by wrapping graphene on carbon nanotube/sulfur composites for rechargeable lithium-sulfur batteries.Materials Letters, 2014, 137: 277-280.
[11]	LI BIN, LI SONG-MEI, LIU JIAN-HUA, et al.Vertically aligned sulfur-graphene nanowalls on substrates for ultrafast lithium-sulfur batteries.Nano Letters, 2015, 15(5): 3073-3079.
[12]	ZHOU GUANG-MING, PEI SONG-FEI, CHENG HUI-MING, et al.A graphene-pure-sulfur sandwich structure for ultrafast, long-life lithium-sulfur batteries.Advanced Materials, 2014, 26(4): 625-631.
[13]	HUANG JIA-QI, ZHANG QIANG, PENG HONG-JIE, et al.Ionic shield for polysulfides towards highly-stable lithium-sulfur batteries.Energy & Environmental Science, 2014, 7(1): 347-353.
[14]	HUANG JIA-QI, ZHUANG TING-ZHOU, ZHANG QIANG, et al.Permselective graphene oxide membrane for highly stable and anti-self-discharge lithium-sulfur batteries.ACS Nano, 2015, 9(3): 3002-3011.
[15]	YAO HONG-BIN, YAN KAI, LI WEI-YANG, et al.Improved lithium-sulfur batteries with a conductive coating on the separator to prevent the accumulation of inactive S-related species at the cathode-separator interface.Energy & Environmental Science, 2014, 7(10): 3381-3390.
[16]	CHENG XIN-BING, PENG HONG-JIE, HUANG JIA-QI, et al.Dual-phase lithium metal anode containing a polysulfide induced solid electrolyte interphase and nanostructured graphene framework for lithium-sulfur batteries.ACS Nano, 2015, 9(6): 6373-6382.
[17]	ZHENG GUANG-YUAN, LEE SEOK-WOO, LIANG ZHENG, et al.Interconnected hollow carbon nanospheres for stable lithium metal anodes.Nat Nanotechnol, 2014, 9(8): 618-623.