Lithium-ion batteries consist primarily of four components: the cathode, the anode, the separator, and the electrolyte. During discharge, lithium ions move from the anode to the cathode; during charging, they flow in the opposite direction. A single battery cell delivers a limited amount of energy and is typically combined with other cells to form a battery pack. Battery packs can then be assembled into battery modules for high‑power‑demand energy storage applications, such as electric vehicles and grid‑scale energy storage. The constituent materials of the cathode, anode, separator, and electrolyte collectively determine the battery’s six key performance characteristics: runtime, safety, cycle life, power output, energy density, and cost.

This paper centers on a design strategy that integrates both ion transport and passivation properties within the electrolyte. It elucidates how the solvation sheath and solvation dynamics of lithium ions influence film‑forming behavior and lithium‑ion transport, and develops an electrolyte system using fluoroethylene carbonate (FEC) and acetonitrile (AN) as solvents and lithium hexafluorophosphate (LiPF6) as the lithium salt. By engineering a solvation structure in which FEC‑dominant coordination ligands are embedded in an AN‑rich environment, the approach effectively addresses the bottlenecks associated with fast‑charging electrolytes. Furthermore, by assembling pouch cells, the study explores the commercial viability of the proposed electrolyte.

Charging involves moving lithium ions from the positive electrode to the negative electrode, while discharging moves them from the negative electrode back to the positive electrode. During these processes, an electric current is generated, providing the vehicle with electrical power. Once all the lithium ions have migrated to the positive electrode, the battery is considered depleted. At that point, an external power source must be connected to the positive terminal to drive the lithium ions back to the negative electrode; when all the ions have reached the negative electrode, the battery is fully charged.

The first type is easier to implement and has already been extensively documented in the literature. What CATL refers to is more likely the second type of battery. In fact, there have previously been reports indicating that gel‑type batteries have been under development. The key difference between gel batteries and conventional lithium‑ion batteries lies in their electrolyte: in standard lithium‑ion cells, the electrolyte is injected after the positive and negative electrodes are assembled; by contrast, in gel batteries, the electrolyte is incorporated during the electrode‑sheet manufacturing process. Moreover, the electrolyte in gel batteries is not liquid—it exists in a jelly‑like state, filling the voids between the electrodes and the separator in a non‑flowing form. The polymer‑metal ion complexation gives rise to this gel‑like structure. With such an electrolyte, the battery’s performance can be significantly enhanced.

Currently, mass‑produced lithium‑ion batteries all use liquid electrolytes. Because these electrolytes are organic solvents, they are highly flammable and require a separator to electrically isolate the positive and negative electrodes. However, during charging and discharging, lithium dendrites that form on the negative electrode can pierce the separator, leading to short circuits; alternatively, mechanical impacts may cause electrolyte leakage, both of which can easily trigger fires.