木质素基碳材料在锂/钠离子电池负极材料中的应用

LIGNIN BASED CARBON USED IN ANODE MATERIALS FOR LITHIUM/ SODIUM IONBATTERIES

杜磊磊

11649157

硕士

材料工程

邓永红

2018-06-04

2018-07-03

哈尔滨工业大学

深圳

随着能源存储应用的迅速扩展，二次储能装置的需求也日益增大。锂离子和钠离子电池是与人类生活密切相关的二次电池，其高比容量负极材料是目前能源领域的研究热点。本文以来自造纸废液的碱性木质素（AL）为原料，通过对其改性合成木质素偶氮聚合物（AL-azo-NO2）并作为碳源，制备出比容量高、循环性能良好的氮掺杂碳包硅的 Si@C 负极材料用于锂离子电池；以及耐长循环、倍率性能好的多孔氮掺杂碳负极材料用于钠离子电池。本研究利用 AL 或者 AL-azo-NO2 作为碳源包覆 50 nm 硅粉制备低成本的锂离子电池硅碳负极材料。其合成利用挥发干燥硅颗粒和碳源的四氢呋喃（THF）均匀悬浮液实现包覆并在氮气氛围下高温碳化。当用作锂离子电池的负极材料时，用AL-azo-NO2 作碳源制备的氮掺杂 Si@C 负极材料（Si@C-AL-azo-NO2）表现出了良好的电化学性能。在 200 mA/g 的电流密度下循环 150 圈后仍然保持 882 mAh/g的高可逆比容量。本研究同时利用 (AL-azo-NO2）作为低成本的碳源通过模板法制备氮掺杂多孔碳用于钠离子电池负极材料。二氧化硅（SiO2）纳米颗粒模板（100 nm 和 200 nm）和 AL-azo-NO2 共同分散于 THF 然后挥发溶剂，高温退火并用 HF 去除 SiO2模板即可得到多孔碳。得到的多孔碳材料呈蜂窝状且孔径均一，拥有较高的比表面积和孔体积。但不同尺寸的模板会影响多孔碳的比表面积和孔体积，进而影响其电化学性能。研究表明，100 nm 粒径模板制备的多孔碳较 200 nm 模板具有更高的比表面积和孔体积，前者表现出更好的倍率性能是因为它具有较大的接触面积和更短的钠离子的传输路径。同时，在 1 A/g 的电流密度下循环 1100 圈后仍然可以保持 100.54 mAh/g 的可逆比容量。在本研究中，一种低成本和丰富的碳源（碱木质素）作为一种前驱体制备了锂离子电池的 N 掺杂的硅碳负极材料和钠离子电池的多孔碳负极材料。证实了在二次储能电池应用木质素是可行的，同时，提供了木质素增值利用的另一条道路。

The demand for secondary energy storage devices is increasing with the rapid extension of energy storage. Among them, lithium ion batteries and sodium ion batteries are closely related to human life and currently the research focuses in energy storage field. In this research, high performance Si@C anode materials for lithium ion batteries and porous carbon for sodium-ion batteries are synthesized based on alkali lignin (AL) and its N-doping derivative azo polymer (AL-azo-NO2) as the carbon precursors.Si@C anode materials for lithium ion batteries were facilely prepared by evaporating solvent THF of the Si NPs/carbon precursor dispersion solution and then the followingcarbonization in nitrogen atmosphere. When used as the anode materials for Li-ion batteries, the nitrogen-doped carbon coated Si NPs (Si@C-AL-azo-NO2) stemmed from the use of AL-azo-NO2 showed superior electrochemical performance. As the results, Si@C-AL-azo-NO2 exhibited a high reversible specific capacity of 882 mAh/g at a current of 200 mA/g over 150 cycles. Porous carbon through hard template (SiO2 nanoparticles of 100 nm and 200 nm)method was synthesized using AL-azo-NO2 as the carbon precursor. The resulting porous carbon showed a honeycomb-like morphology with uniform nanopores, surface area and volume. However, different size of template affects the surface area and pore volume of the porous carbon. When used as anode materials for Na-ion batteries, the porous carbon AL-aN-100 (100 nm SiO2 as template) has larger surface area and pore volume than that of AL-aN-200 (200 nm SiO2 as template). The former showed better rate performance is attributed that it has a large contact area and short distance of Na+transportation. As the results, it exhibited a high reversible specific capacity of 100.54 mAh/g at a current of 1A/g over 1100 cycles.In this study, a low-cost and abundant carbon source (alkaline lignin) as a precursor to synthesis the N-doping Si@C anode for Li-ion batteries and porous carbon as anodefor Na-ion batteries. Verifying the lignin’s application in rechargeable secondary batteries is feasible, meanwhile, providing another path for high-value applications of lignin.

木质素 锂离子电池 钠离子电池 负极 硅碳 氮掺杂多孔碳

Lignin Lithium ion battery Sodium ion batteries anode Si@C Nitrogen doped porous carbon

中文

联合培养

南方科技大学

杜磊磊. 木质素基碳材料在锂/钠离子电池负极材料中的应用[D]. 深圳. 哈尔滨工业大学,2018.