An Artificial SEI Layer Based on an Inorganic Coordination Polymer with Self‐Healing Ability for Long‐Lived Rechargeable Lithium‐Metal Batteries

Abstract

Upon immersion of a lithium (Li) anode into a diluted 0.05 to 0.20 M dimethoxyethane-solution of the phosphoric acid derivative (CF 3 CH 2 O) 2 P(O)OH (HBFEP), an artificial solid electrolyte interphase (SEI) is generated on the Li-metal surface. Hence, HBFEP reacts on the surface to the corresponding Li salt (LiBFEP), which is a Li-ion conducting inorganic coordination polymer. This film exhibits -due to the reversibly breaking ionic bonds -self-healing ability upon cycling-induced volume expansion of Li. The presence of LiBFEP as the major component in the artificial SEI is proven by ATR-IR and XPS measurements. SEM characterization of HBFEP-treated Li samples reveals porous layers on top of the Li surface with at least 3 μm thickness. LiÀ Li symmetrical cells with HBFEP-modified Li electrodes show a three-to almost fourfold cycle-lifetime increase at 0.1 mA cm À 2 in a demanding model electrolyte that facilitates fast battery failure (1 M LiOTf in TEGDME). Hence, the LiBFEP-enriched layer apparently acts as a Li-ion conducting protection barrier between Li and the electrolyte, enhancing the rechargeability of Li electrodes.

Facile Fabrication of Highly Porous 3D Sponge‐Like Si@C Composites as High‐Performance Anode Materials for Lithium‐Ion Batteries

“…Furthermore, the C 1s high‐resolution XPS profile of the MP−Si@C 1 composite consisted of three peaks with binding energies of 284.9, 286.4, and 288.9 eV, which were assigned to the Si−C, C−C, and O−C=O bonds, correspondingly (Figure S1c). In addition, the O 1s XPS profile of the MP−Si@C 1 composite was deconvoluted into three main peaks at binding energies of 531.7, 532.9, and 533.8 eV, which were ascribed to CO 3 2− , SiO/SiO 2 , and C−O bonds, respectively [37–39] …”

Exploration and Application of Self‐Healing Strategies in Lithium Batteries

“…deposited a fluoro‐organic phosphoric acid on Li metal resulting in the formation of artificial self‐healing SEI layers on its surface by adopting the immersion method. [ 139 ] Tang et al. designed a novel artificial interfacial layer, consisting mainly of lithium nitride (Li 3 N) which conduct Li ions and block electrons, by in situ reaction of Cu 3 N in the solid electrolyte with Li metal.…”

“…[138] Likewise, Beichel et al deposited a fluoro-organic phosphoric acid on Li metal resulting in the formation of artificial self-healing SEI layers on its surface by adopting the immersion method. [139] Tang et al designed a novel artificial interfacial layer, consisting mainly of lithium nitride (Li 3 N) which conduct Li ions and block electrons, by in situ reaction of Cu 3 N in the solid electrolyte with Li metal. [140] This interfacial membrane could interact with the solid electrolyte, making the surface of the anode material without obvious cracks before and after the cycle.…”

High‐Rate Discharge Minimizes Volume Expansion of Lithium Metal Electrodes under Lean Electrolyte and High Areal Capacity Conditions

“…In recent years, significant research efforts have focused on the stabilization of Li metal electrode, employing various strategies such as novel electrolyte compositions, artificial solidelectrolyte interphase (SEI) layers, and precise control of stack pressure. [8][9][10][11][12][13][14][15][16] These studies have made notable progress in enhancing the cycle life of LMBs. In particular, several investigations have empirically demonstrated the improvement of cycle life in LMBs by adopting a relatively higher-rate discharge protocol, commonly referred to as an asymmetric chargedischarge protocol.…”

“…In recent years, significant research efforts have focused on the stabilization of Li metal electrode, employing various strategies such as novel electrolyte compositions, artificial solid‐electrolyte interphase (SEI) layers, and precise control of stack pressure [8–16] . These studies have made notable progress in enhancing the cycle life of LMBs.…”