Weakly Solvating Solution Enables Chemical Prelithiation of Graphite–SiO_x Anodes for High-Energy Li-Ion Batteries

Abstract

Although often overlooked in anode research, the anode’s initial Coulombic efficiency (ICE) is a crucial factor dictating the energy density of a practical Li-ion battery. For next-generation anodes, a blend of graphite and Si/SiO x represents the most practical way to balance capacity and cycle life, but its low ICE limits its commercial viability. Here, we develop a chemical prelithiation method to maximize the ICE of the blend anodes using a reductive Li–arene complex solution of regulated solvation power, which enables a full cell to exhibit a near-ideal energy density. To prevent structural degradation of the blend during prelithiation, we investigate a solvation rule to direct the Li+ intercalation mechanism. Combined spectroscopy and density functional theory calculations reveal that in weakly solvating solutions, where the Li+–anion interaction is enhanced, free solvated-ion formation is inhibited during Li+ desolvation, thereby mitigating solvated-ion intercalation into graphite and allowing stable prelithiation of the blend. Given the ideal ICE of the prelithiated blend anode, a full cell exhibits an energy density of 506 Wh kg–1 (98.6% of the ideal value), with a capacity retention after 250 cycles of 87.3%. This work highlights the promise of adopting chemical prelithiation for high-capacity anodes to achieve practical high-energy batteries.

Recent Advances in Electrolytes for “Beyond Aqueous” Zinc‐Ion Batteries

“…Weakly coordinating salts are widely discussed in lithium‐ion batteries and magnesium‐ion batteries, [ 104–107 ] while there are few reports for ZIBs. Inspired by magnesium‐ion batteries, Yang et al.…”

“…Weakly coordinating salts are widely discussed in lithiumion batteries and magnesium-ion batteries, [104][105][106][107] while there are few reports for ZIBs. Inspired by magnesium-ion batteries, Yang et al proved that the anions of zinc tetrakis(perfluorotert-butoxy) aluminate (Zn[TPFA] 2 ) is unlikely to exist in the innermost part of the Zn 2+ solvation shell in a most solvent such as AN, triglyme (G3), and THF (Figure 9a), and ZnTPFA 2 has high anodic stability with a wide voltage window for ZIBs through experiments and calculations.…”

Control of cyclic stability and volume expansion on graphite–SiOx–C hierarchical structure for Li-ion battery anodes

“…Prelithiaion strategy, to compensate for irreversible Li loss before full-cell fabrication, could be achieve more than 90% of ICE. 45–48 This is expected to be helpful in practical applications in the future.…”

Structural regulation chemistry of lithium ion solvation for lithium batteries

“…Besides, additives can impact the Li + solvation structure from multiple aspects, such as changing the behavior of Li + in the electrolyte through special groups in the molecular structures, regulating the electrode‐electrolyte interphase compositions, and promoting the interaction between anions and Li + , etc 3,21,41,50,51 . Therefore, it is capable to adjust the performance of Li batteries by manipulating the Li + solvation structure 32,52,53 …”

“…3,21,41,50,51 Therefore, it is capable to adjust the performance of Li batteries by manipulating the Li + solvation structure. 32,52,53 At present, there are some excellent reviews on the electrolytes of Li batteries, such as high-voltage electrolytes, 54 additive modifications, 55 and solvent optimization. 56 Different from them, this review will focus on the structural regulation chemistry of Li + solvation for Li batteries.…”