Crowning Metal Ions by Supramolecularization as a General Remedy toward a Dendrite‐Free Alkali‐Metal Battery

Abstract

Alkali metals have low potentials and high capacities, making them ideal anodes for next‐generation batteries, but they suffer major problems, including dendrite growth and low Coulombic efficiency (CE). Achieving uniform metal deposition and having a reliable solid electrolyte interphase (SEI) are the basic requirements for overcoming these problems. Here, a general remedy is reported for various alkali‐metal anodes by the supramolecularization of alkali‐metal cations with crown ethers that follows a size‐matching rule. The positively charged supramolecular complex provides electrostatic shielding layers to regulate metal deposition and suppress dendrite formation. More promisingly, it reforms electric double layers and drives the production of organic‐dominated SEIs with improved flexibility that can accommodate large volume changes. The high flexibility of SEIs during metal deposition and dissolution reduces the amount of dead metal and improves CE and cycling stability. Specifically, a 200% excess Li‐based full cell has a capacity retention of ≈100% after 100 cycles. This crown‐like supramolecularization strategy is a new chemistry that may be used for the production of dendrite‐free metal‐anode‐based batteries not limited to the cases with alkali metal. It is also expected as a practical technology to improve the uniformity of coatings produced in the electrodeposition industry.

Crowning Lithium Ions in Hole‐Transport Layer toward Stable Perovskite Solar Cells

“…The 12-crown-4 induced chemical shift can be explained by a different coordination environment. [26] This phenomenon is in agreement with the result of 1 H NMR as discussed above. After O 2 -bubbling, the dominating peak position remains almost the same for the control precursor and the signal at the positive side slightly increases as the formation of Li 2 O 2 that contains Li vacancies.…”

“…Particularly, 12‐crown‐4 has an interior cavity diameter that matches well with Li + ‐ion size. [ 26 ] In this study, it was chosen to promote the dissociation of LiTFSI and increase the solubility through the following coordination reaction: LiTFSI+ 12‐crown‐4 → Li(12‐crown‐4) + + TFSI – . After adding 12‐crown‐4, LiTFSI can be dissolved quickly in CB and we successfully prepared transparent precursor solution without requiring acetonitrile.…”

Constructing Self‐Adapting Electrostatic Interface on Lithium Metal Anode for Stable 400 Wh kg−1 Pouch Cells

“…[34] It is well known that electrostatic shielding can regulate the electric field distribution and thus fundamentally modulate metal ion deposition morphology in electroplating. [35,36] Cationic additives such as Rb + and Am + are promising "flattening reagents" for electrostatic shielding, as they can effectively prevent dendrites by reducing the local current density caused by the aforementioned tip effect. [37][38][39] However, they commonly have a higher reduction potential than lithium metal, for example, Rb + , −2.98 V versus SHE; Am + , −2.79 V versus SHE, and are likely lead to the codeposition with Li + .…”

Roll‐To‐Roll Fabrication of Zero‐Volume‐Expansion Lithium‐Composite Anodes to Realize High‐Energy‐Density Flexible and Stable Lithium‐Metal Batteries

“…However, the significant volume expansion of the Li metal during charging results in poor cycling stability as a result of the dendritic deposition and broken solid electrolyte interphase. from various perspectives, including heteroatom-doping Li metal, [7][8][9][10] optimizing electrolyte components, [11][12][13][14] engineering protective layers, [15][16][17][18] and constructing solid electrolytes. [19,20] These strategies have been proven useful for stabilizing Limetal anodes to some extent, but they are still facing huge volume expansion due to their hostless nature.…”