Lithium Nafion–Modified Li_6.05Ga_0.25La₃Zr₂O_11.8F_0.2 Trilayer Hybrid Solid Electrolyte for High-Voltage Cathodes in All-Solid-State Lithium-Metal Batteries

Abstract

All-solid-state batteries containing ceramic–polymer solid electrolytes are possible alternatives to lithium-metal batteries containing liquid electrolytes in terms of their safety, energy storage, and stability at elevated temperatures. In this study we prepared a garnet-type Li6.05Ga0.25La3Zr2O11.8F0.2 (LGLZOF) solid electrolyte modified with lithium Nafion (LiNf) and incorporated it into poly­(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrixes. We used a solution-casting method to obtain bilayer (Bi-HSE) and trilayer (Tri-HSE) hybrid solid electrolytes. A layer of functionalized multiwalled carbon nanotubes (f-MWCNTs) coated with LiNf (LiNf@f-MWCNT) in the Tri-HSE led to good compatibility with the polymer slurry and adhered well to the Li anode, thereby improving the interfacial contact at the electrode–solid electrolyte interface and suppressing dendrite growth. The Tri-HSE membrane displayed high ionic conductivity (5.6 × 10–4 S cm–1 at 30 °C), a superior Li+ transference number (0.87), and a wide electrochemical window (0–5.0 V vs Li/Li+). In addition, Li symmetrical cells incorporating this hybrid electrolyte possessed excellent interfacial stability over 600 h at 0.1 mA cm–2 and a high critical current density (1.5 mA cm–2). Solid-state lithium batteries having the structure LiNf@LiNi0.8Co0.1Mn0.1O2/Tri-HSE/Li delivered excellent room-temperature stable cycling performance at 0.5C, with a capacity retention of 85.1% after 450 cycles.

Uniform Lithium Plating for Dendrite-Free Lithium Metal Batteries: Role of Dipolar Channels in Poly(vinylidene fluoride) and PbZrxTi1–xO3 Interface

“…(a) Voltage profiles of the lithium plating/stripping curves of Li/Li symmetrical cells with the PVDF–PZT CPE, PVDF SPE, and PVDF-Al 2 O 3 CPE at a current density of 0.1 mA cm –2 and 25 °C. (b) Comparison of the cycling time of Li/PVDF–PZT CPE/Li symmetrical cells at 25 °C with those of the Li/PVDF-based CPE/Li symmetrical cells reported in the literature. ,,− SEM images of the cycled Li surface from Li/PVDF–PZT CPE/Li and Li/PVDF SPE/Li symmetrical cells at current densities of (c) 0.05 mA cm –2 , (d) 0.1 mA cm –2 , and (e) 0.2 mA cm –2 , respectively. (f) C 1s, (g) F 1s, and (h) S 2p XPS spectra of cycled Li anodes from Li/PVDF–PZT CPE/Li and Li/PVDF SPE/Li symmetrical cells.…”

“…(d) Charge/discharge curves of PVDF–PZT CPE full cells during rate capacities. (e) Cycling performances of NCM811//Li cells with the PVDF–PZT CPE and PVDF SPE full cells at 0.5 C. Charge/discharge curves of the (f) PVDF–PZT CPE and (g) PVDF SPE full cells at 0.5 C. (h) Comparison of the long cycling performance of NCM811/PVDF–PZT CPE/Li cells at 25 °C with reported PVDF-based CPE cells reported in the literature. ,,,,− …”

State-of-the-Art of Solid-State Electrolytes on the Road Map of Solid-State Lithium Metal Batteries for E-Mobility

“…A garnet-type Li 6.05 Ga 0.25 La 3 Zr 2 O 11.8 F 0.2 (LGLZOF) solid electrolyte modified with lithium Nafion (LiNf) exhibited a superior Li transference number of 0.87, with a capacity retention of 85.1% after 450 cycles in a full cell. One wt % LiNf@f-MWCNT polymer matrix when coated to the side of the electrolyte facing the Li anode is expected to suppress Li dendrite formation, providing a higher Coulombic efficiency of 99.6% . In another study, three-dimensional (3D) interconnected c-LALZO framework not only enabled one to suppress dendrite but also improved the upper limit voltage up to 4.5 V .…”

Ceramic-in-Polymer Hybrid Electrolytes with Enhanced Electrochemical Performance

“…Upon implementation of such composite polymer electrolytes (CPEs), new Li + transport pathways are theoretically accessible either due to Li + transport through the bulk ceramic or at the interface between polymer and ceramic domains. − Note that especially the latter is considered to afford highly conductive Li + transport. , However, preferential Li + pathways may be affected by interactions with the polymer matrix, ceramic composition and content as well as the presence of additional plasticizer/mobilizer agents . A synergistic effect combining plasticizers such as tetraglyme or PC with ceramics within a CPE recently demonstrated a boosted Li + conductivity, though sufficient long-term cycling in full cells was missing, rendering further works necessary. , In addition to a homogenous distribution of ceramic particles within the polymer matrix, CIP materials can be designed as layered or gradient structures. − A ceramic-rich layer at the Li metal electrode may regulate Li + flux during deposition, even at a capacity utilization of 15 mAh cm –2 , or form a layer with ultrahigh mechanical strength to mitigate Li dendrite growth . Zhu et al showed that a BaTiO 3 -rich layer electrospun at the cathode generates a protective film and stabilizes the interphase .…”

“… 27 , 28 In addition to a homogenous distribution of ceramic particles within the polymer matrix, CIP materials can be designed as layered or gradient structures. 29 − 32 A ceramic-rich layer at the Li metal electrode may regulate Li + flux during deposition, even at a capacity utilization of 15 mAh cm –2 , 30 or form a layer with ultrahigh mechanical strength to mitigate Li dendrite growth. 31 Zhu et al showed that a BaTiO 3 -rich layer electrospun at the cathode generates a protective film and stabilizes the interphase.…”