Direct Observation of the Growth of Lithium Dendrites on Graphite Anodes by Operando EC‐AFM

Abstract

Lithium dendrite growth is one of the most challenging problems affecting the safety performance of lithium-ion batteries (LIBs). It causes low Coulombic efficiency as well as safety hazards for LIBs. Understanding the evolution process of Li-dendrite growth at the nanoscale is critical for solving this problem. Herein, an in situ electrochemical atomic force microscopy (EC-AFM) investigation of the initial Li deposition in ethylene carbonate (EC)-based and fluoroethylene carbonate (FEC)-based electrolytes on graphite anodes is reported. These results show that the solid electrolyte interphase (SEI) formed from the FEC-based electrolyte can suppress Li-dendrite growth. The FEC-based electrolyte induces formation of LiF-rich SEI films, which are harder and denser than those formed in an EC-based electrolyte. Due to its better mechanical properties and larger resistance, the SEI layer formed from the FEC-based electrolyte is sufficient to prevent reduction of Li + ions and deposition of Li + ions on the anode surface. These results demonstrate that EC-AFM is a powerful in situ technique for the study of lithium-dendrite growth.

Advances in Understanding Materials for Rechargeable Lithium Batteries by Atomic Force Microscopy

“…also find that the SEI formed in FEC‐based electrolyte can suppress Li dendrite growth because fluorine‐rich FEC‐based electrolyte can promote formation of compact and robust SEI which can suppress dendrite growth. The compact SEI also slows down the Li + intercalation and prevents reduction of Li + to deposit on graphite surface . The interphase engineering can protect Li metal from electrolyte and stabilize the Li plating/stripping.…”

“…The compact SEI also slows down the Li + intercalation and prevents reduction of Li + to deposit on graphite surface. [65] The interphase engineering can protect Li metal from electrolyte and stabilize the Li plating/stripping. Li et al design a flexible Li polyacrylic acid (LiPAA) polymer layer on Li metal.…”

A Cell for Controllable Formation and In Operando Electrochemical Characterization of Intercalation Materials for Aqueous Metal‐Ion Batteries

“…These curves exhibit a plateau that is typical for (dis)charge curves of batteries. The mean working potential difference is calculated as ≈1.57 V at 360 C. Small Methods 2019, 3,1900445 For the initial discharge half cycles of the C-rate 360 C one finds an average specific capacity of ≈18.2 mAh g −1 . In terms of the absolute capacity, this value is comparable to the absolute capacity of the MnHCM anode.…”

“…Small Methods 2019, 3,1900445 In Figure 3, exemplary measurement results from the final battery tests of the NiHCF-MnHCM model battery at 360 C are presented. Figure 3A,B depicts the voltage difference ΔE versus specific capacity and energy curves of the first full (dis)charge cycle, respectively.…”

“…Those achievements would not, however, be possible if experimental research schemes involving advanced measurements, cell designs, and experimental protocols had not been developed, enabling maximal informative power from minimum amount of experiments. [2][3][4][5][6][7][8][9][10][11] Today, aqueous metal-ion batteries are electrochemical methods and battery tests with quartz crystal microbalance measurements that are performed in operando. In this new cell design, multiple electrodes can be synthesized and characterized individually, and afterward can be operated together in order to measure a full battery using only a single setup.…”