All-Solid-State Lithium Batteries: Li⁺-Conducting Ionomer Binder for Dry-Processed Composite Cathodes

Abstract

All-solid-state lithium batteries (ASSLBs) are considered promising alternatives to current lithium-ion batteries as their use poses less of a safety risk. However, the fabrication of composite cathodes by the conventional slurry (wet) process presents technical challenges, such as limited stability of sulfide electrolytes against organic solvents and the increase of ionic resistance due to the use of insulating polymer binder. Herein, we develop a composite cathode fabricated using a solvent-free (dry) process. The composite cathode is prepared with a Li +conducting ionomer binder, poly(tetrafluoroethylene-co-perfluoro(3-oxa-4-pentenesulfonic acid)) lithium salt. The ionomer facilitates Li + transport and ensures good interfacial contact between the active material (LiNi 0.7 Co 0.1 Mn 0.2 O 2 ), conducting carbon, and solid electrolyte (Li 6 PS 5 Cl) during cycling. Consequently, an ASSLB featuring a composite cathode with an ionomer delivers a high discharge capacity of 180.7 mAh g −1 (3.05 mAh cm −2 ) at 0.1 C and demonstrates stable cycling performance, retaining 90% of its initial capacity after 300 cycles at 0.5 C.

Stabilizing Li4SnS4 Electrolyte from Interface to Bulk Phase with a Gradient Lithium Iodide/Polymer Layer in Lithium Metal Batteries

“…Subsequently, the effect of the PEO–LiI modification layer on the interface morphology and composition distribution between Li metal and LSS electrolyte was analyzed by cryo-TEM (Figure ). In Figure a, Li deposits under the LSS/PEO–LiI electrolyte were random blocks rather than Li spheres or Li dendrites frequently observed in liquid cells, which may be related to the relatively slow ion conduction in the solid state electrolyte. ,− On basis of the elemental mappings, the I, Sn, and S elements were found to be evenly distributed across the interface. Notably, the mass content of the I element was 18.7 wt % (Figures d and S15), indicating the great contributor of I-containing substances to SEI.…”

Toward High Rate Performance Solid‐State Batteries

“…[ 82 ] A recent study introduced poly(tetrafluoroethylene‐ co ‐perfluoro(3‐oxa‐4‐pentenesulfonic acid)) lithium salt, called “ionomer,” as a conductive dry binder in ASSBs (Figure 6d). [ 83 ] The ionomer could facilitate Li + transport and enable good interfacial contact between CAMs (LiNi 0.7 Co 0.1 Mn 0.2 O 2 ), conducting carbon, and SE (LPSCl) during cycling. The cathode prepared with the ionomer binder showed significantly improved cycle and rate performances compared to the cathodes prepared without the binder and with the PTFE dry binder.…”

Insights into interfacial chemistry of Ni-rich cathodes and sulphide-based electrolytes in all-solid-state lithium batteries

“…Lithium argyrodite SSE Li 6 PS 5 Cl is of great interest owing to its high ionic conductivity and easy processability. 123 However, the poor electrochemical stability between Ni-rich CAMs and Li 6 PS 5 Cl presents many problems. The detailed reaction mechanisms have been investigated by various methods, including XPS and TOF-SIMS, in recent years.…”