Chemical Industry and Engineering Progress ›› 2022, Vol. 41 ›› Issue (5): 2555-2565.DOI: 10.16085/j.issn.1000-6613.2021-1011

• Materials science and technology • Previous Articles     Next Articles

Three dimensional self-supporting Co, N, S co-doped porous carbon derived from paulownia wood for Li-O2 batteries

LIANG Huagen1(), QI Zhengwei2, JIA Linhui1, GAI Zejia2, JING Shengyu2, YIN Shibin3()   

  1. 1.Low Carbon Energy Institute, China University of Mining and Technology, Xuzhou 221008, Jiangsu, China
    2.School of Information and Control Engineering, China University of Mining and Technology, Xuzhou 221008, Jiangsu, China
    3.College of Chemistry and Chemical Engineering, MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials, Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials, Guangxi University, Nanning 530004, Guangxi, China
  • Received:2021-05-12 Revised:2021-06-17 Online:2022-05-24 Published:2022-05-05
  • Contact: YIN Shibin

锂-氧气电池用泡桐木衍生三维自支撑Co、N、S共掺杂多孔炭

梁华根1(), 齐正伟2, 贾林辉1, 盖泽嘉2, 荆胜羽2, 尹诗斌3()   

  1. 1.中国矿业大学低碳能源研究院,江苏 徐州 221008
    2.中国矿业大学信息与控制工程学院,江苏 徐州 221008
    3.广西大学化学化工学院,有色金属及材料加工新技术教育部重点实验室,广西有色金属及特色材料加工重点 实验室,广西 南宁 530004
  • 通讯作者: 尹诗斌
  • 作者简介:梁华根(1985—),男,副研究员,研究方向为电催化与能源材料。E-mail:lianghg@cumt.edu.cn
  • 基金资助:
    国家自然科学基金(21908242);广西大学有色金属及特色材料加工重点实验室开放基金(2021GXYSOF10)

Abstract:

Lithium-oxygen (Li-O2) batteries are considered as the most promising new generation energy storage devices because of their high theoretical energy density and environmental friendliness. However, large overpotential, low practical energy density and poor cycle life are the huge obstacles to their practical application. Since the insoluble and insulating discharge products (Li2O2) gradually form on the surface or in the pores of cathode during the discharging process, these products will block the diffusion channel of O2/electrolyte and cover the catalytic active sites. In addition, the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) require noble-metal-based materials as catalyst to reduce the overpotential and achieve high electrochemcial efficiency. However, high cost and scarcity of the noble-metal catalysts hinder their large scale applications. Development of economically viable and highly efficient noble-metal-free electrocatalysts is extremely urgent, especially for heteroatom-doped carbons as the most promising candidates. In this paper, a novel Co, N and S co-doped three-dimensional self-standing porous carbon (wd-NSC) was prepared as cathode for Li-O2 battery using melamine and thiourea as nitrogen and sulfur sources via one-step pyrolysis of paulownia wood in NaCl/CoCl2 mixed molten salt medium. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results found that the wd-NSC inherited the original vertical channel structure of paulownia wood, and formed porous carbon fiber network on the surface and inside the channels of wd-NSC. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) confirmed that N and S were successfully doped into the C skeleton, while Co might exist in the form of single atom or clusters. Nitrogen adsorption/desorption isotherms showed that the wd-NSC possess hierarchical porous structure with pore sizes ranging from micropore to macropore. Raman spectra certified that the introduction of S increased the defect degree of wd-NSC. At a current density of 0.05mA/cm2, the discharge specific capacity of wd-NSC reached to 12.83mA·h/cm2, and exhibited a good rate capability and cycling stability (at a current density of 0.1mA/cm2 and a limited capacity of 0.5mA·h/cm2, the cell can maintain 125 cycles). The excellent electrochemical performance of wd-NSC in the Li-O2 battery could be attributed to the synergistic effect of three-dimensional hierarchical porous structure and Co, N, S heteroatoms co-doping. The above results demonstrated that this study provided a promising strategy to produce efficiency and low-cost cathodes for practical application in Li-O2 batteries.

Key words: lithium-oxygen (Li-O2) battery, air electrode, three-dimensional self-standing, molten salt, doped, electrochemistry, nanostructure, preparation

摘要:

正极是锂-氧气(Li-O2)电池的电化学反应场所,其直接决定了电池性能。本研究采用泡桐木为原材料,在NaCl/CoCl2混合熔融盐介质中,以三聚氰胺和硫脲为氮源和硫源,一步热解炭化制备出Co、N、S共掺杂的三维自支撑多孔炭材料(wd-NSC),并直接用作Li-O2电池正极。利用X射线衍射、扫描电镜、透射电镜、氮气吸脱附、拉曼光谱、X射线光电子能谱等对所获三维自支撑多孔炭材料的形貌、晶体结构与化学成分进行了表征。研究结果表明,Co、N、S共掺杂的三维自支撑多孔炭材料表现出高比容量(在0.05mA/cm2的电流密度下,放电比容量可达12.83mA·h/cm2)和出色的循环稳定性(在电流密度为0.1mA/cm2和限定容量为0.5mA·h/cm2下,循环寿命可达125次),优异的电池性能可归因于三维分级多孔结构及Co、N、S共掺杂的协同作用。

关键词: 锂-氧气电池, 空气电极, 三维自支撑, 熔融盐, 掺杂, 电化学, 纳米结构, 制备

CLC Number: 

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