Acta Phys. -Chim. Sin. ›› 2021, Vol. 37 ›› Issue (11): 2008033.doi: 10.3866/PKU.WHXB202008033

Special Issue: Energy and Materials Chemistry

• COMMUNICATION • Previous Articles     Next Articles

Single-Atom Cobalt Coordinated to Oxygen Sites on Graphene for Stable Lithium Metal Anodes

Haodong Shi1,2,3, Yaguang Li1,2, Pengfei Lu1,2, Zhong-Shuai Wu1,2,*()   

  1. 1 State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, China
    2 Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, China
    3 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-08-13 Accepted:2020-09-08 Published:2020-09-14
  • Contact: Zhong-Shuai Wu E-mail:wuzs@dicp.ac.cn
  • About author:Zhong-Shuai Wu, Email: wuzs@dicp.ac.cn; Tel.: +86-411-82463036
  • Supported by:
    the National Key R@D Program of China(2016YBF0100100);the National Natural Science Foundation of China(51872283);the National Natural Science Foundation of China(21805273);the Liaoning BaiQianWan Talents Program, Liaoning Revitalization Talents Program(XLYC1807153);the Natural Science Foundation of Liaoning Province(20180510038);Dalian Institute Of Chemical Physics(DICP ZZBS201708);Dalian Institute Of Chemical Physics(DICP ZZBS201802);Dalian Institute Of Chemical Physics(DICP I202032);Dalian Institute Of Chemical Physics and Qingdao Institute of Biomass Energy and Bioprocess Technology(DICP&QIBEBT UN201702);the Dalian National Laboratory For Clean Energy (DNL), CAS, DNL Cooperation Fund, CAS(DNL180310);the Dalian National Laboratory For Clean Energy (DNL), CAS, DNL Cooperation Fund, CAS(DNL180308);the Dalian National Laboratory For Clean Energy (DNL), CAS, DNL Cooperation Fund, CAS(DNL201912);the Dalian National Laboratory For Clean Energy (DNL), CAS, DNL Cooperation Fund, CAS(DNL201915)

Abstract:

Lithium (Li)-based batteries are the dominant energy source for consumer electronics, grid storage, and electrified transportation. However, the development of batteries based on graphite anodes is hindered by their limited energy density. With its ultrahigh theoretical capacity (3860 mAh∙g−1), low redox potential (−3.04 V), and satisfactorily low density (0.54 g∙cm−3), Li metal is the most promising anode for next-generation high-energy-density batteries. Unfortunately, the limited cycling life and safety issues raised by dendrite growth, unstable solid electrolyte interphase, and "dead Li" have inhibited their practical use. An effective strategy is to develop a suitable lithiophilic matrix for regulating initial Li nucleation behavior and controlling subsequent Li growth. Herein, single-atom cobalt coordinated to oxygen sites on graphene (Co-O-G SA) is demonstrated as a Li plating substrate to efficiently regulate Li metal nucleation and growth. Owing to its dense and more uniform lithiophilic sites than single-atom cobalt coordinated to nitrogen sites on graphene (Co-N-G SA), high electronic conductivity, and high specific surface area (519 m2∙g−1), Co-O-G SA could significantly reduce the local current density and promote the reversibility of Li plating and stripping. As a result, the Co-O-G SA based Li anodes exhibited a high Coulombic efficiency of 99.9% at a current density of 1 mA∙cm−2 with a capacity of 1 mAh∙cm−2, and excellent rate capability (high current density of 8 mA∙cm−2). Even at a high plating capacity of 6 mAh∙cm−2, the Co-O-G SA electrode could stably cycle for an ultralong lifespan of 1300 h. In the symmetric battery, the Co-O-G SA based Li anode (Co-O-G SA/Li) possessed a stable voltage profile of 18 mV for 780 h at 1 mA∙cm−2, and even at a high current density of 3 mA∙cm−2, its overpotential maintained a small hysteresis of approximately 24 mV for > 550 h. Density functional theory calculations showed that the surface of Co-O-G SA had a stronger interaction with Li atoms with a larger binding energy, −3.1 eV, than that of Co-N-G SA (−2.5 eV), leading to a uniform distribution of metallic Li on the Co-O-G SA surface. More importantly, when matched with a sulfur cathode, the resulting Co-O-G SA/lithium sulfur full batteries exhibited a high capacity of 1002 mAh∙g−1, improved kinetics with a small polarization of 191 mV, and an ultralow capacity decay rate of 0.036% per cycle for 1000 cycles at 0.5C (1C = 1675 mA∙g−1) with a steady Coulombic efficiency of nearly 100%. Therefore, this work provides novel insights into the coordination environment of single atoms for the chemistry of Li metal anodes for high-energy-density batteries.

Key words: Single atom, Coordination environment, Lithiophilic site, Li dendrite, High-energy-density lithium battery

MSC2000: 

  • O646