ABSTRACT
Ionic liquid electrolytes (ILEs) are promising to develop high-safety and high-energy-density lithium-metal batteries (LMBs). Unfortunately, ILEs normally face the challenge of sluggish Li+ transport due to increased ions' clustering caused by Coulombic interactions. Here a type of anion-reinforced solvating ILEs (ASILEs) is discovered, which reduce ions' clustering by enhancing the anion-cation coordination and promoting more anions to enter the internal solvation sheath of Li+ to address this concern. The designed ASILEs, incorporating chlorinated hydrocarbons and two anions, bis(fluorosulfonyl) imide (FSI-) and bis(trifluoromethanesulfonyl) imide (TFSI-), aim to enhance Li+ transport ability, stabilize the interface of the high-nickel cathode material (LiNi0.8Co0.1Mn0.1O2, NCM811), and retain fire-retardant properties. With these ASILEs, the Li/NCM811 cell exhibits high initial specific capacity (203 mAh g-1 at 0.1 C), outstanding capacity retention (81.6% over 500 cycles at 1.0 C), and excellent average Coulombic efficiency (99.9% over 500 cycles at 1.0 C). Furthermore, an Ah-level Li/NCM811 pouch cell achieves a notable energy density of 386 Wh kg-1, indicating the practical feasibility of this electrolyte. This research offers a practical solution and fundamental guidance for the rational design of advanced ILEs, enabling the development of high-safety and high-energy-density LMBs.
ABSTRACT
The performance of zinc-ion batteries is severely hindered by the uncontrolled growth of dendrites and the severe side reactions on the zinc anode interface. To address these challenges, a weak-water-coordination electrolyte is realized in a peptone-ZnSO4 -based electrolyte to simultaneously regulate the solvation structure and the interfacial environment. The peptone molecules have stronger interaction with Zn2+ ions than with water molecules, making them more prone to coordinate with Zn2+ ions and then reducing the active water in the solvated sheath. Meantime, the peptone molecules selectively adsorb on the Zn metal surface, and then are reduced to form a stable solid-electrolyte interface layer that can facilitate uniform and dense Zn deposition to inhabit the dendritic growth. Consequently, the Zn||Zn symmetric cell can exhibit exceptional cycling performance over 3200 h at 1.0 mA cm-2 /1.0 mAh cm-2 in the peptone-ZnSO4 -based electrolyte. Moreover, when coupled with a Na2 V6 O16 ·3H2 O cathode, the cell exhibits a long lifespan of 3000 cycles and maintains a high capacity retention rate of 84.3% at 5.0 A g-1 . This study presents an effective approach for enabling simultaneous regulation of the solvation structure and interfacial environment to design a highly reversible Zn anode.
