Designing Polymer‐in‐Salt Electrolyte and Fully Infiltrated 3D Electrode for Integrated Solid‐State Lithium Batteries

Abstract

Solid-state lithium batteries (SSLBs) are promising owing to enhanced safety and high energy density but plagued by the relatively low ionic conductivity of solid-state electrolytes and large electrolyte-electrode interfacial resistance. Herein, we design a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based polymer-in-salt solid electrolyte (PISSE) with high room-temperature ionic conductivity (1.24 10 À4 S cm À1 ) and construct a model integrated TiO 2 /Li SSLB with 3D fully infiltration of solid electrolyte. With forming aggregated ion clusters, unique ionic channels are generated in the PISSE, providing much faster Li + transport than common polymer electrolytes. The integrated device achieves maximized interfacial contact and electrochemical and mechanical stability, with performance close to liquid electrolyte. A pouch cell made of 2 SSLB units in series shows high voltage plateau (3.7 V) and volumetric energy density comparable to many commercial thin-film batteries.

Stable Interface Chemistry and Multiple Ion Transport of Composite Electrolyte Contribute to Ultra‐long Cycling Solid‐State LiNi0.8Co0.1Mn0.1O2/Lithium Metal Batteries

“…The 6 Li peaks intensity increase of Li2 site in rinsed LNs obtained from the cycled PVLN-15 electrolyte is much larger than that of Li1 site (Figure 5h), indicating that the Li2 site transports Li-ion more actively due 6 Li and g) 7 Li NMR spectra of PVLN-15 electrolyte before and after cycling of 6 Li/PVLN-15/ 6 Li symmetric cell. h) 6 Li NMR spectra of pristine and rinsed LATP after cycling. i) Quantified contributions to Li-ion transport of components in PVLN-15 electrolyte.…”

“…These results suggest that all the components participate in Li-ion transport. By simulating the integrated peaks for each component before and after cycling, the contributions to Li-ion transport are quantified on basis of ratios between the 6 Li peaks integration increase. [24] It can be obtained that 10.81 %a nd 23.64 % 6 Li migration occurs in Li1 and Li2 site,r espectively.T he 6 Li transport of [Li(DMF) x ] + -PVDF accounts for 15.80 %.…”

“…[2] Several SPEs have been reported up to now,i ncluding polyethylene (PEO)-based, [3] polyacrylonitrile (PAN)-based, [4] poly(propylene carbonate) (PPC)based, [5] and poly(vinylidene fluoride) (PVDF)-based. [6] In comparison with other SPEs,t he PVDF-based electrolytes with the merits of high mechanical strength and excellent thermal stability exhibit particularly appealing, [7] but they face many serious issues due to the existence of DMF residual solvent. TheDMF presents strong interactions with Li salts to form [Li(DMF) x ] + solvation molecules,which are transported by PVDF chains based on the interactions between PVDF and [Li(DMF) x ] + to achieve high ionic conductivity.…”

“…a) AFM image and b) nano-IR overlap of C=Ov ibration of DMF at 1664 cm À1 .T he green color areas mean the stronger absorption intensity.c)HAADF-TEM image and corresponding EELS element mapping of d) Li and e) Ti element. f)6 Li and g)7 Li NMR spectra of PVLN-15 electrolyte before and after cycling of6 Li/PVLN-15/6 Li symmetric cell. h)6 Li NMR spectra of pristine and rinsed LATP after cycling.…”

“…f)6 Li and g)7 Li NMR spectra of PVLN-15 electrolyte before and after cycling of6 Li/PVLN-15/6 Li symmetric cell. h)6 Li NMR spectra of pristine and rinsed LATP after cycling. i) Quantified contributions to Li-ion transport of components in PVLN-15 electrolyte.…”