Researchers from Tsinghua University and China University of Geosciences have used an ultrathin indium sheet to construct a stabilized lithium-rich hybrid anode with fast interfacial ion transport. The artificial alloy layer demonstrates an enhanced ionic conductivity with an order of magnitude higher than that of the pristine solid electrolyte interphase.
An open-access paper on their work is published in the RSC journal Chemical Communications.
Increasingly high attention has been paid on the development of high energy-density rechargeable lithium metal batteries in recent times due to the highest theoretical capacity and the lowest standard electrode potential (Cap=3860 mAh g-1, E=-3.040 V) of metallic lithium anode. Unfortunately, one of the major barrier impeding the practical implementation of the metallic lithium anodes is the dendritic structure formation, ascribed to the denounced mass and charge transfer across the lithium/electrolyte interphase with uneven lithium metal electrodeposition. Thus, the platted fresh lithium tends to react instantaneously with liquid electrolyte since lithium is thermodynamically unstable against organic solvents. Therefore, more parasitic reaction and electrolyte consumption can come about in the subsequent continual cycling and results in low Coulombic efficiency (CE) and raises safety issues.
To meet the demand of high energy density Li- O2 and Li-S rechargeable batteries performing at room temperature, advanced metallic lithium anode is required with dendrite suppression.
Here, an ultrathin indium sheet was fabricated and used to construct a lithium-rich Li-In hybrid anode by a facile superficial alloying. The alloying process between indium and metallic lithium is fast and spontaneous due to the larger electronegativity difference. The ultrathin indium sheet was obtained by a simple rolling method. Specifically, the artificial interphase protects the lithium metal against the parasitic reactions and provides a compliant layer to accommodate the volume change of electrode caused by the alloying and platting processes.—Sun et al.
In the study, the team used 1M LiPF6in ethylene carbonate-dimethyl carbonate (EC/DMC) solvent for the liquid electrolyte.
With a reduced diffusion barrier and improved charge transfer at the artificial interface, the hybrid anode realized the uniform lithium electrodeposition and considerable dendrite suppression.
Coupled with LiNi5Co3Mn2O2 (NCM-532) cathodes, this hybrid anode shows an impressive reversibility, with 90% retention after 120 cycles.
Bin Sun, Jialiang Lang, Kai Liu, Naveed Hussain, Minghao Fang and Hui Wu (2019) “Promoting a highly stable lithium metal anode by superficial alloying with an ultrathin indium sheet” Chem. Commun. doi: 10.1039/C8CC08934E