The Entanglement of Li Capping and Deposition: An Operando Optical Microscopy Study

Abstract

Dendrite growth and low Coulombic efficiency impede the practical application of Li-metal batteries. As such, monitoring Li deposition and stripping in real-time is crucial to understanding the fundamental lithium growth kinetics. This work presents an operando optical microscopic technique that enables precise current density control and quantification of Li layer properties (i.e., thickness and porosity) to study Li growth in various electrolytes. We discover the robustness and porosity of the remaining capping layer after the Li stripping process as the critical features governing the subsequent dendrite propagation behavior, resulting in distinct capping and stacking phenomena that affect Li growth upon cycling. While dendrite propagation quickly occurs through the fracture of the fragile Li capping layer, uniform Li plating/stripping can be facilitated by the compact and robust capping layer even at high current densities. This technique can be extended to evaluate dendrite suppression treatments in various metal batteries, providing in-depth information on metal growth mechanisms.

Tailoring a multi-system adaptable gel polymer electrolyte for the realization of carbonate ester and ether-based Li-SPAN batteries

“…Notably, a piece of detached dendrites floats on the mossy Li deposition layer after 60 min (which belongs to the exfoliation of dead Li), indicating the distribution of inhomogeneous SEI crystalline grains, leading to pinched dendrites detaching from the main structure of the Li deposition layer. 57,58 By stark contrast, more uniformly Li dendrites grow in PFGPE during the first 15 min. With the gradual increase in plating time, Li deposits become homogeneously thickened with larger granular sizes and less tortuosity.…”

Macroscale Inhomogeneity in Electrochemical Lithium‐Metal Plating Triggered by Electrolyte‐Dependent Gas Phase Evolution

“…We took advantage of the optical microscopy (OM) as its imaging scale provides the most relevant information about the electrodelevel morphological evolution. [57][58][59][60][61][62][63][64][65][66][67] Homemade in situ electrochemical OM cells were constructed with lithium metal foil, a copper electrode, and the electrolyte in a transparent cuvette, as depicted in Figure S6 (Supporting Information). The lithium growth behavior was probed in real time, and was recorded with a digital camera connected to the optical microscope (Videos S1-S3, Supporting Information).…”

Solid Electrolyte Interphase Recombination on Graphene Nanoribbons for Lithium Anode

“…Interestingly, it was found that the lithium anode in different electrolytes (LiPF 6 in carbonate solvents, such as ethylene carbonate, dimethyl carbonate, and diethyl carbonate, and LiTFSI in ether solvents, such as 1,3-dioxolane and 1,2-dimethoxyethane) formed different composition SEIs and had different electrochemical performances in overpotential of lithium deposition, cycling lifespan, and Coulombic efficiency (CE). , A lithium anode has better electrochemical performance in a LiTFSI-ether electrolyte than that in a LiPF 6 -carbonate electrolyte. , The Cui group found that a LiTFSI-based electrolyte resulted in the formation of a compact SEI structure with rich inorganic components via studying the structure and chemical composition of lithium dendrites . Hayoung Park found that lithium grew rapidly infrequent nucleation in a LiTFSI-based electrolyte with high Li + conductivity and flexibility of the SEI .…”