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Nano Research

Article Title

Highly stable lithium anode enabled by self-assembled monolayer of dihexadecanoalkyl phosphate

Authors

Lei Zheng, School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Feng Guo, School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei 230026, China i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Tuo Kang, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Jin Yang, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Ya Liu, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Wei Gu, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Yanfei Zhao, Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinses Academy of Science (CAS), Suzhou 215123, China
Hongzhen Lin, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Yanbin Shen, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Wei Lu, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China
Liwei Chen, i-Lab, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China In-situ Center for Physical Sciences, School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200240, China

Keywords

Li metal anode, Li-CNT, self-assembled monolayer, depth of discharge, Coulombic efficiency

Abstract

Li has been considered as the ultimate anode material for high energy density secondary Li batteries. However, its practical application has been limited due to its low Coulombic efficiency (CE) and the formation of lithium dendrites. Recently, we have developed a microspherical Li-carbon nanotube (Li-CNT) composite material passivated with octadecylphosphonic acid (OPA) self-assembled monolayer (SAM) exhibiting suppressed lithium dendrite formation and improved environmental/electrochemical stability. In this work, we demonstrated the significantly enhanced passivation effects of a SAM using dihexadecanoalkyl phosphate (DHP), a molecule that is comprised of double hydrophobic alkyl chains and forms a denser SAM on surfaces with large curvature. As a result, the DHP SAM delivers superior environmental and electrochemical stability to the OPA passivated Li-CNT material. In specific, the DHP passivated Li-CNT composite (DHP-Li-CNT) delivers a high CE of 99.25% under a 33.3% depth of discharge (DOD) at 1 C, when it is paired with a LiFePO4 cathode. The evolution of the SAM during cycling and the effects of DOD and current density on the CE of the DHP-Li-CNT anode have also been investigated. The improved SAM passivation constitutes an important step in achieving the goal of practically applicable Li anodes.

Graphical Abstract

Publisher

Tsinghua University Press

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