Work

Ionic Liquid Enabled High‐Energy‐Density Solid‐State Lithium Batteries with High‐Areal‐Capacity Cathode and Scaffold‐Supported Composite Electrolyte

Year: 2025

Type: article

Abstract: Solid‐state lithium batteries (SSLBs) with composite solid electrolytes (CSEs) offer enhanced energy density and high safety. However, their performance is hindered by large thickness and limited Li⁺ conductivity of CSEs, and large electrode/electrolyte interface resistance. This study develops an 18 µm‐thick CSE using a polyethylene scaffold, which incorporates garnet‐type Li 6.25 La 3 Zr 2 Ga 0.25 O 12 (LLZGO) oxide and an ionic liquid (IL) additive in a poly(vinylidene fluoride‐co‐hexafluoropropylene)/polypropylene carbonate matrix, achieving a high ionic conductivity of 8.6 × 10 −4 S cm −1 at 30 °C. The IL increases Li + conduction of the CSE and reduces the interfacial resistance. The constructed LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM‐811)||CSE||Li cell shows remarkable charge–discharge performance. This study also integrates LLZGO and N ‐propyl‐ N ‐methylpyrrolidinium bis(trifluorosulfonyl)imide (PMP‐TFSI) IL into a thick NCM‐811 cathode. The synergy between LLZGO and PMP‐TFSI within the cathode is examined. A high‐mass‐loading cathode with ≈20 mg cm −2 NCM‐811 is developed. The resulting composite cathode||CSE||Li cell achieves an areal capacity of ≈4 mAh cm −2 . With the proposed scaffold‐supported CSE and thick NCM/LLZGO/IL composite cathode, the projected energy density of the resulting anode‐free pouch cell is ≈420 Wh kg −1 . This study demonstrates a scalable and effective strategy for fabricating an oxide‐based SSLB with a high energy density and enhanced Li + transport properties.

Source: Small

DOI: 10.1002/smll.202503865