Wetting Phenomena and their Effect on the Electrochemical Performance of Surface‐Tailored Lithium Metal Electrodes in Contact with Cross‐linked Polymeric Electrolytes

Abstract

Li metal batteries (LMBs) containing cross‐linked polymer electrolytes (PEs) are auspicious candidates for next‐generation batteries. However, the wetting behavior of PEs on uneven Li metal surfaces has been neglected in most studies. Herein, it is shown that microscale defect sites with curved edges play an important role in a wettability‐dependent electrodeposition. The wettability and the viscoelastic properties of PEs are correlated, and the impact of wettability on the nucleation and diffusion near the Li|PE interface is distinguished. It is found that the curvature of the edges is a key factor for the investigation of wetting phenomena. The appearance of microscale defects and phase separation are identified as main causes for erratic nucleation. It is emphasized that the implementation of stable and consistent long‐term cycling performance of LMBs using PEs requires a deeper understanding of the “soft‐solid”–solid contact between PEs and inherently rough Li metal surfaces.

Cation‐Assisted Lithium‐Ion Transport for High‐Performance PEO‐based Ternary Solid Polymer Electrolytes

“…Cross-linking allows increasing the IL content in the TSPEs to lift the ionic conductivities even higher (6.6 10 À4 Scm À1 and 1.4 10 À3 Scm À1 at, respectively 40 8 8Cand 60 8 8Cfor cl-20:2:4 O7 ). Even though higher ionic conductivities can be reached for the cl-20:2:4 O7 membrane and IL phase separation might be favorable to improve the performance and wetting [24] in LFP k Li cells,T SPEs with lower IL content were used in the following to avoid partial crystallization at an operating temperature of 40 8 8C.…”

In Situ Electrolyte Gelation to Prevent Chemical Crossover in Li Metal Batteries

“…Such gel has a high viscosity of 4191.47 cp, meanwhile it is still able to wet the electrode due to the high fluidity as compared to pure SSEs, thus greatly improving the interfacial contact between the electrolyte and the lithium anode with original defects. [ 40,41 ]…”

“…Such gel has a high viscosity of 4191.47 cp, meanwhile it is still able to wet the electrode due to the high fluidity as compared to pure SSEs, thus greatly improving the interfacial contact between the electrolyte and the lithium anode with original defects. [40,41] Another important parameter, Li transfer number (t Li+ ) is always used to evaluate the electrochemical capability of the electrolyte. The cells were assembled by placing GPEs between two pure Li metal.…”

Lithium Deposition in Single-Ion Conducting Polymer Electrolytes

“…23,24 Therefore, surficial pre-treatment of the metal anode, explicitly surface modification of the Li-metal as well as the initial oxidation layer thereon, is critical to reveal the Li deposition behavior, but is rarely reported even in liquid-electrolyte systems. [24][25][26][27][28][29][30] In addition to the as-received Li-metal, hexane washed 25,31,32 and roll-pressed 26 Limetal electrodes were prepared to explore the Li deposition under different surface conditions. Hexane constitutes a suitable solvent for Li treatment since it is inert toward metallic Li but dissolves various organic compounds.…”