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

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 (...

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Bibliographic Details
Published in:Nano research 2020-05, Vol.13 (5), p.1324-1331
Main Authors: Zheng, Lei, Guo, Feng, Kang, Tuo, Yang, Jin, Liu, Ya, Gu, Wei, Zhao, Yanfei, Lin, Hongzhen, Shen, Yanbin, Lu, Wei, Chen, Liwei
Format: Article
Language:English
Subjects:
Anodes
Atomic/Molecular Structure and Spectra
Batteries
Biomedicine
Biotechnology
Carbon nanotubes
Chemistry and Materials Science
Composite materials
Condensed Matter Physics
Dendrites
Electrochemistry
Electrode materials
Flux density
Hydrophobicity
Lithium
Materials Science
Monolayers
Nanotechnology
Passivity
Research Article
Self-assembled monolayers
Self-assembly
Stability
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Summary: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 LiFePO 4 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.
ISSN:1998-0124
1998-0000
DOI:10.1007/s12274-019-2565-7