An official website of the United States government
Abstract A new concentrated ternary salt ether‐based electrolyte enables stable cycling of lithium metal battery (LMB) cells with high‐mass‐loading (13.8 mg cm−2, 2.5 mAh cm−2) NMC622 (LiNi0.6Co0.2Mn0.2O2) cathodes and 50 μm Li anodes. Termed “CETHER‐3,” this electrolyte is based on LiTFSI, LiDFOB, and LiBF4with 5 vol% fluorinated ethylene carbonate in 1,2‐dimethoxyethane. Commercial carbonate and state‐of‐the‐art binary salt ether electrolytes were also tested as baselines. With CETHER‐3, the electrochemical performance of the full‐cell battery is among the most favorably reported in terms of high‐voltage cycling stability. For example, LiNixMnyCo1–x–yO2(NMC)‐Li metal cells retain 80% capacity at 430 cycles with a 4.4 V cut‐off and 83% capacity at 100 cycles with a 4.5 V cut‐off (charge at C/5, discharge at C/2). According to simulation by density functional theory and molecular dynamics, this favorable performance is an outcome of enhanced coordination between Li+and the solvent/salt molecules. Combining advanced microscopy (high‐resolution transmission electron microscopy, scanning electron microscopy) and surface science (X‐ray photoelectron spectroscopy, time‐of‐fight secondary ion mass spectroscopy, Fourier‐transform infrared spectroscopy, Raman spectroscopy), it is demonstrated that a thinner and more stable cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) are formed. The CEI is rich in lithium sulfide (Li2SO3), while the SEI is rich in Li3N and LiF. During cycling, the CEI/SEI suppresses both the deleterious transformation of the cathode R‐3m layered near‐surface structure into disordered rock salt and the growth of lithium metal dendrites.
more »
« less
Operando EDXRD Study of All‐Solid‐State Lithium Batteries Coupling Thioantimonate Superionic Conductors with Metal Sulfide
Abstract Sulfide solid‐state electrolytes have remarkable ionic conductivity and low mechanical stiffness but suffer from relatively narrow electrochemical and chemical stability with electrodes. Therefore, pairing sulfide electrolytes with the proper cathode is crucial in developing stable all‐solid‐state Li batteries (ASLBs). Herein, one type of thioantimonate ion conductor, Li6+xGexSb1−xS5I, with different compositions is systematically synthesized and studied, among these compositions, an outstanding ionic conductivity of 1.6 mS cm−1is achieved with Li6.6Ge0.6Sb0.4S5I. To improve the energy density and advance the interface compatibility, a metal sulfide FeS2cathode with a high theoretical capacity (894 mAh g−1) and excellent compatibility with sulfide electrolytes is coupled with Li6.6Ge0.6Sb0.4S5I in ASLBs without additional interface engineering. The structural stabilities of Li6.6Ge0.6Sb0.4S5I and FeS2during cycling are characterized by operando energy dispersive X‐ray diffraction, which allows rapid collection of structural data without redesigning or disassembling the sealed cells and risking contamination by air. The electrochemical stability is assessed, and a safe operating voltage window ranging from 0.7≈2.4 V (vs. In–Li) is confirmed. Due to the solid confinement in the ASLBs, the Fe0aggregation and polysulfides shuttle effects are well addressed. The ASLBs exhibit an outstanding initial capacity of 715 mAh g−1at C/10 and are stable for 220 cycles with a high capacity retention of 84.5% at room temperature.
more »
« less
- Award ID(s):
- 1924534
- PAR ID:
- 10454439
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Energy Materials
- Volume:
- 11
- Issue:
- 3
- ISSN:
- 1614-6832
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract The energetic chemical reaction between Zn(NO3)2and Li is used to create a solid‐state interface between Li metal and Li6.4La3Zr1.4Ta0.6O12(LLZTO) electrolyte. This interlayer, composed of Zn, ZnLixalloy, Li3N, Li2O, and other species, possesses strong affinities with both Li metal and LLZTO and affords highly efficient conductive pathways for Li+transport through the interface. The unique structure and properties of the interlayer lead to Li metal anodes with longer cycle life, higher efficiency, and better safety compared to the current best Li metal electrodes operating in liquid electrolytes while retaining comparable capacity, rate, and overpotential. All‐solid‐state Li||Li cells can operate at very demanding current–capacity conditions of 4 mA cm−2–8 mAh cm−2. Thousands of hours of continuous cycling are achieved at Coulombic efficiency >99.5 % without dendrite formation or side reactions with the electrolyte.more » « less
-
Abstract The performance of all‐solid‐state batteries (ASSBs) relies on the Li+transport and stability characteristics of solid electrolytes (SEs). Li3PS4is notable for its stability against lithium metal, yet its ionic conductivity remains a limiting factor. This study leverages local structural disorder via O substitution to achieve an ionic conductivity of 1.38 mS cm−1with an activation energy of 0.34 eV for Li3PS4−xOx(x = 0.31). Optimal O substitution transforms Li+transport from 2D to 3D pathways with increased ion mobility. Li3PS3.69O0.31exhibits improvements in the critical current density and stability against Li metal and retains its electrochemical stability window compared with Li3PS4. The practical implementation of Li3PS3.69O0.31in ASSBs half‐cells, particularly when coupled with TiS2as the cathode active material, demonstrates substantially enhanced capacity and rate performance. This work elucidates the utility of introducing local structural disorder to ameliorate SE properties and highlights the benefits of strategically combining the inherent strengths of sulfides and oxides via creating oxysulfide SEs.more » « less
-
Abstract In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li2S‐P2S5(LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce2S3) and without Ce2S3doping. The crystal structure, ionic conductivity, and chemical stability of Li7P3S11glass‐ceramic electrolytes were examined at varying temperatures (250–350°C). The results indicated that the highest ionic conductivity of 3.15 × 10−4S cm−1for pure Li7P3S11was observed at a temperature of 325°C. By incorporating 1 wt% Ce2S3and subjecting it to a heat treatment at 250°C, the glass ceramic electrolyte attained a remarkable ionic conductivity of 7.7 × 10−4(S cm−1) at 25°C. Furthermore, it exhibited a stable and extensive electrochemical potential range, reaching up to 5 volts when compared to the Li/Li+reference electrode. By tuning the glass transition and crystallization temperature, cerium doping seems to make Li7P3S11more chemically stable, compared to its original 70Li2S‐30P2S5counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P2S74‐(pyro‐thiophosphate) to PS43−and P2S64−. Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li7P2.9Ce0.1S11electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries.more » « less
-
Abstract Rechargeable solid‐state sodium metal batteries (SSMBs) experience growing attention owing to the increased energy density (vs Na‐ion batteries) and cost‐effective materials. Inorganic sulfide‐based Na‐ion conductors also possess significant potential as promising solid electrolytes (SEs) in SSMBs. Nevertheless, due to the highly reactive Na metal, poor interface compatibility is the biggest obstacle for inorganic sulfide solid electrolytes such as Na3SbS4to achieve high performance in SSMBs. To address such electrochemical instability at the interface, new design of sulfide SE nanostructures and interface engineering are highly essential. In this work, a facile and straightforward approach is reported to prepare 3D sulfide‐based solid composite electrolytes (SCEs), which utilize porous Na3SbS4(NSS) as a self‐templated framework and fill with a phase transition polymer. The 3D structured SCEs display obviously improved interface stability toward Na metal than pristine sulfide. The assembled SSMBs (with TiS2or FeS2as cathodes) deliver outstanding electrochemical cycling performance. Moreover, the cycling of high‐voltage oxide cathode Na0.67Ni0.33Mn0.67O2(NNMO) is also demonstrated in SSMBs using 3D sulfide‐based SCEs. This study presents a novel design on the self‐templated nanostructure of SCEs, paving the way for the advancement of high‐energy sodium metal batteries.more » « less
