Bridging Evolution of the Solvation Sheath to Rigid‐Soft Coupling and Low‐Resistance Solid Electrolyte Interface for Fast‐Charging and Ultrastable Bi Anode

Abstract

The key issue holding back the application of Bi‐based lithium‐ion battery (LIB) is the rigorous requirements of low interfacial resistance, superior mechanical stability, and high ion conductivity of solid electrolyte interface (SEI). In this work, inspired by human musculoskeletal tissues, a multifunctional SEI with low interfacial resistance and synergistic rigid‐soft features is in situ constructed through the interfacial evolution of PF6 anion‐derived solvation sheath at the Bi anode, facilitating Li ion conductivity, and SEI/electrolyte interface wettability, alleviating the enormous volumetric expansion of Bi anodes, and offering superior Bi/SEI/electrolyte compatibility during long‐term cycles. Attributed to these superiorities, an unprecedented cycling stability can be obtained, i.e., 94.4% capacity retention at 2.6 C after 1000 cycles and 89.6% capacity retention at 5.2 C after 1300 cycles. When this anode is coupled with a LiFePO4 cathode, the full cell delivers superior cyclability with 85.2% capacity retention at 0.6 C after 100 cycles. This research provides new insight into handling the interfacial compatibility and fast‐charging issues of Bi‐based LIB.

Building a rigid-soft coupling interphase by a reduction–oxidation collaborative approach with lithium difluorobis(oxalato) phosphate additives

“…This suggests that the oxidation products are highly viscoelastic and more flexible. 28 In other words, the oxidation-product-dominated SEI layer can adhere to the electrode surface and deform when the graphite particles expand, rather than brittle failure and cracking. The discrepancies between the mechanical characteristics of the reduction and oxidation products are consistent with the SEM findings.…”

Fast-Charging Phosphorus-Based Anodes: Promises, Challenges, and Pathways for Improvement

“…Last but not least, the properties of SEI crucially rely on the compositions of the electrolytes and are often critical in determining the XFC capacity . Due to it being electronically insulating, the SEI layer inhibits the long-lasting decomposition of electrolyte while permitting the migration of ions.…”

“…Last but not least, the properties of SEI crucially rely on the compositions of the electrolytes and are often critical in determining the XFC capacity. 90 Due to it being electronically insulating, the SEI layer inhibits the long-lasting decomposition of electrolyte while permitting the migration of ions. Therefore, • Electron transfer 95 • LiPF 6 -EC:EMC 99 • Stabilizing Li metal through the better interfacial mechanical stability than LiF 102 • Ion transport 96 • LiPF 6 -EC:DEC 100 • Mechanical property 97 • EC-based electrolytes 101 • Solubility 98…”

Anionic Activity in Fast-Charging Batteries: Recent Advances, Prospects, and Challenges

“…Concerning the aforementioned quandary, tremendous research has been conducted on the structure, − composition, − and mechanical properties − of electrode–electrolyte interfaces to develop a stable, homogeneous, and kinetically favorable interfacial film for fast-charging batteries with high safety and reliability. Since the inductive effect of polyanions can be utilized to change the M–O covalency in the bulk phase to develop polyanion cathodes with high stability and safety, the design of polyanion-based ion-conductor coatings on the electrode surface as the artificial interfacial layer is expected to reduce the side reactions and accelerate transport kinetics for fast-charging applications compared to the traditional organic-rich SEI. − …”