Synergistic Effect of the Anode Interface of Garnet-Type All-Solid-State Batteries

Next-generation lithium-ion batteries must have high energy density and safety, making the development of all-solid-state batteries imperative. One of the biggest advantages of an all-solid-state lithium-ion battery (ASSLIB) is that its alloy uses lithium metal as an anode while ignoring its flammability and other dangers. Herein, high-conductivity garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) was chosen as the solid electrolyte part of an all-solid-state battery. A composite anode was formed by melting Li and MXene-MAX together, reducing the interface impedance from 566 to 55 Ω cm2. The Li-MXene|LLZTO|LFP full battery displayed a high initial discharge capacity of 163.0 mAh g–1 and a Coulombic efficiency of 97.0% and maintained 90.2% of its discharge capacity over 100 cycles, but it did not maintain a good overpotential. Therefore, the synergistic effect of Li-MXene-Pt will highly improve the performance of the full battery because of its high initial discharge capacity of 150.0 mAh g–1 and Coulombic efficiency of 95.5%, discharge capacity maintained at 93.3% over 100 cycles, and low overpotential of 0.04 V

In Situ and Low-Cost Improvement of the Lithium Anode Interface in Garnet-Type Solid-State Electrolytes

In recent years, the development of electric vehicles and environmental concerns have made necessary improvements in the energy density and safety of lithium-ion batteries. Therefore, the development of all-solid-state lithium-ion batteries (ASSLIBs) has become imperative. One advantage of ASSLIBs is their potential for downsizing with the use of lithium metal as the anode. However, in this study, a garnet-type solid electrolyte (Li6.75La3Zr1.75Ta0.25O12) was used, which has low reactivity with lithium metal. Thus, interface modification using CaCl2 was employed to form a Li–Ca–Cl composite anode. The interfacial resistance was remarkably reduced to 7 Ω cm2, and the symmetric cell exhibited stable cycling for 1200 h at room temperature and a current density of 0.1 mA cm–2. The voltage ranged from ±15 to ±16 mV. The full cell demonstrated a high initial discharge capacity of 149.2 mA h g–1 and a Coulombic efficiency of 98.0% while maintaining a discharge capacity retention of 91.3% after 100 cycles. These findings lay a solid foundation for future commercial applications as interface modification was achieved through a simple spin-coating process using low-cost CaCl2 (0.7 USD g–1)

In Situ and Low-Cost Improvement of the Lithium Anode Interface in Garnet-Type Solid-State Electrolytes

In recent years, the development of electric vehicles and environmental concerns have made necessary improvements in the energy density and safety of lithium-ion batteries. Therefore, the development of all-solid-state lithium-ion batteries (ASSLIBs) has become imperative. One advantage of ASSLIBs is their potential for downsizing with the use of lithium metal as the anode. However, in this study, a garnet-type solid electrolyte (Li6.75La3Zr1.75Ta0.25O12) was used, which has low reactivity with lithium metal. Thus, interface modification using CaCl2 was employed to form a Li–Ca–Cl composite anode. The interfacial resistance was remarkably reduced to 7 Ω cm2, and the symmetric cell exhibited stable cycling for 1200 h at room temperature and a current density of 0.1 mA cm–2. The voltage ranged from ±15 to ±16 mV. The full cell demonstrated a high initial discharge capacity of 149.2 mA h g–1 and a Coulombic efficiency of 98.0% while maintaining a discharge capacity retention of 91.3% after 100 cycles. These findings lay a solid foundation for future commercial applications as interface modification was achieved through a simple spin-coating process using low-cost CaCl2 (0.7 USD g–1)

Short-Range Electronic Interactions between Vanadium and Molybdenum in Bimetallic SAPO‑5 Catalysts Revealed by Hyperfine Spectroscopy

Engineering two cooperative sites into a catalyst implies the onset of synergistic effects related to the existence of short-range electronic interactions between two metal components. However, these interactions and the relative structure–property correlations are often difficult to obtain. Here we show that hyperfine spectroscopy has the potential to reveal the presence of V4+–O–Mo6+ linkages assessing the degree of spin density transfer from paramagnetic V4+ species to proximal oxo-bridged Mo6+ metal ions. The dimer species were prepared by adsorption of Mo(CO)6 in the pores of SAPO-5, followed by thermal decomposition and oxidation and subsequent grafting of anhydrous VCl4(g) followed by hydrolysis and dehydration. The metal species react with SAPO protons during the exchange process and generate new Lewis acid sites, which act as redox centers. X- and Q-band EPR and HYSCORE experiments have been employed to monitor the local environment of V4+ species obtaining direct evidence for spin delocalization over 27Al, 31P, 95Mo, and 97Mo nuclei, demonstrating the presence of bimetallic V–O–Mo well-defined structures

Spontaneous In Situ Formation of Lithium Metal Nitride in the Interface of Garnet-Type Solid-State Electrolyte by Tuning of Molten Lithium

All-solid-state lithium-ion batteries (ASSLIBs) have attracted much attention owing to their high energy density and safety and are known as the most promising next-generation LIBs. The biggest advantage of ASSLIBs is that it can use lithium metal as the anode without any safety concerns. This study used a high-conductivity garnet-type solid electrolyte (Li6.75La3Zr1.75Ta0.25O12, LLZTO) and Li-Ga-N composite anode synthesized by mixing melted Li with GaN. The interfacial resistance was reduced from 589 to 21 Ω cm2, the symmetry cell was stably cycled for 1000 h at a current density of 0.1 mA cm–2 at room temperature, and the voltage range only changed from ±30 to ±40 mV. The full cell of Li-Ga-N|LLZTO|LFP exhibited a high first-cycle discharge capacity of 152.2 mAh g–1 and Coulombic efficiency of 96.5% and still maintained a discharge capacity retention of 91.2% after 100 cycles. This study also demonstrated that Li-Ga-N had been shown as two layers. Li3N shows more inclined to be closer to the LLZTO side. This method can help researchers understand what interface improvements can occur to enhance the performance of all-solid-state batteries in the future

Extensively Reducing Interfacial Resistance by the Ultrathin Pt Layer between the Garnet-Type Solid-State Electrolyte and Li–Metal Anode

All-solid-state Li-ion batteries (ASSLIBs), also known as next-generation batteries, have attracted much attention due to their high energy density and safety. The best advantage of ASSLIBs is the Li–metal anodes that could be used without safety issues. In this study, a highly conductive garnet solid electrolyte (Li6.75La3Zr1.75Ta0.25O12, LLZTO) was used in the ASSLIB, and a Pt film was used to modify the surface of LLZTO to prove the solution of the Li–metal anode for LLZTO. Li–Pt alloy was synthesized to improve the wettability and contact of the interface. The interfacial resistance was reduced by 21 times, at only 9 Ω cm2. The symmetric cell could stably cycle over 3500 h at a current density of 0.1 mA cm–2. The full cell of Li|Li–Pt|LLZTO|LiFePO4 and Li|Li–Pt|LLZTO|LiMn0.8Fe0.2PO4 achieved high stability in terms of battery performance. Point-to-point contact transformed into homogeneous surface contact made the Li-ion flux faster and more stable. This surface modification method could provide researchers with a new choice for fixing interface issues and promoting the application of high-performance ASSLIBs in the future

All-Solid-State Li-Ion Battery Using Li_1.5Al_0.5Ge_1.5(PO₄)₃ As Electrolyte Without Polymer Interfacial Adhesion

Solid-state lithium-ion batteries are promising candidates for energy storage devices that meet the requirements to reduce CO₂ emissions. NASICON-type solid-state electrolytes (SSE) are most promising materials as electrolytes for high-performance lithium ion batteries because of their good stability and high ionic conductivity. In this study, we successfully fabricate NASICON-based Li_1.5Al_0.5Ge_1.5(PO₄)₃ lithium fast-ion conductors through melt-quenching with post-crystallization. The effect of crystallization temperature on the structure of LAGP and their ionic conductivity is systematically studied using Rietveld analysis of Synchrotron X-ray powder diffraction patterns, multinuclear magnetic resonance, and electrochemical analysis, revealing that the mobility of Li ion is dependent on crystallization temperature. The glass–ceramic LAGP annealed at 800 °C for 8 h exhibits the highest conductivity of 0.5 mS cm^–1 at room temperature. Moreover, we report the viability of the prepared LAGP glass−ceramic as a solid electrolyte in Li-ion batteries without polymer adhesion. The cycling of Li/LAGP/LFP all-solid-state cell, provides a stable cycling lifetime of up to 50 cycles. This approach demonstrates that LAGP glass–ceramic can have good contact with the electrodes without interfacial layer and can deliver a reasonable discharge capacity after 50 cycles

Defect-Mediated Energy States in Brookite Nanorods: Implications for Photochemical Applications under Ultraviolet and Visible Light

The photochemical properties of brookite nanorods are systematically explored using light-induced electron-paramagnetic resonance (EPR) techniques at different wavelengths spanning the UV–vis region of the electromagnetic spectrum (355–650 nm). Under UV irradiation, electron–hole pairs are generated, leading to the stabilization of paramagnetic centers, primarily Ti3+ and O– species at the surface. Visible light irradiation at low temperature results in a unique pair of EPR signals, including electrons trapped at titanium cations and a distinct signal resonating at g = 2.004. The pair of signals disappears after annealing at room temperature, indicating that recombination pathways with trapped electrons are available. The chemical reactivity of the different photogenerated species is tested using electron and holes scavengers. While peculiar light-harvesting capabilities are observed for the brookite nanorods, experiments carried out in the presence of a hole scavenger indicate a limited potential for oxidative processes under visible light

Dual Structure of a Vanadyl-Based Molecular Qubit Containing a Bis(β-diketonato) Ligand

We designed [VO­(bdhb)] (1′) as a new electronic qubit containing an oxovanadium­(IV) ion (S = 1/2) embraced by a single bis­(β-diketonato) ligand [H2bdhb = 1,3-bis­(3,5-dioxo-1-hexyl)­benzene]. The synthesis afforded three different crystal phases, all of which unexpectedly contain dimers with formula [(VO)2(bdhb)2] (1). A trigonal form (1h) with a honeycomb structure and 46% of solvent-accessible voids quantitatively transforms over time into a monoclinic solvatomorph 1m and minor amounts of a triclinic solventless phase (1a). In a static magnetic field, 1h and 1m have detectably slow magnetic relaxation at low temperatures through quantum tunneling and Raman mechanisms. Angle-resolved electron paramagnetic resonance (EPR) spectra on single crystals revealed signatures of low-dimensional magnetic behavior, which is solvatomorph-dependent, being the closest interdimer V···V separations (6.7–7.5 Å) much shorter than intramolecular V···V distances (11.9–12.1 Å). According to 1H diffusion ordered spectroscopy (DOSY) and EPR experiments, the complex adopts the desired monomeric structure in organic solution and its geometry was inferred from density functional theory (DFT) calculations. Spin relaxation measurements in a frozen toluene-d8/CD2Cl2 matrix yielded Tm values reaching 13 μs at 10 K, and coherent spin manipulations were demonstrated by Rabi nutation experiments at 70 K. The neutral quasi-macrocyclic structure, featuring nuclear spin-free donors and additional possibilities for chemical functionalization, makes 1′ a new convenient spin-coherent building block in quantum technologies

Dual Structure of a Vanadyl-Based Molecular Qubit Containing a Bis(β-diketonato) Ligand

We designed [VO­(bdhb)] (1′) as a new electronic qubit containing an oxovanadium­(IV) ion (S = 1/2) embraced by a single bis­(β-diketonato) ligand [H2bdhb = 1,3-bis­(3,5-dioxo-1-hexyl)­benzene]. The synthesis afforded three different crystal phases, all of which unexpectedly contain dimers with formula [(VO)2(bdhb)2] (1). A trigonal form (1h) with a honeycomb structure and 46% of solvent-accessible voids quantitatively transforms over time into a monoclinic solvatomorph 1m and minor amounts of a triclinic solventless phase (1a). In a static magnetic field, 1h and 1m have detectably slow magnetic relaxation at low temperatures through quantum tunneling and Raman mechanisms. Angle-resolved electron paramagnetic resonance (EPR) spectra on single crystals revealed signatures of low-dimensional magnetic behavior, which is solvatomorph-dependent, being the closest interdimer V···V separations (6.7–7.5 Å) much shorter than intramolecular V···V distances (11.9–12.1 Å). According to 1H diffusion ordered spectroscopy (DOSY) and EPR experiments, the complex adopts the desired monomeric structure in organic solution and its geometry was inferred from density functional theory (DFT) calculations. Spin relaxation measurements in a frozen toluene-d8/CD2Cl2 matrix yielded Tm values reaching 13 μs at 10 K, and coherent spin manipulations were demonstrated by Rabi nutation experiments at 70 K. The neutral quasi-macrocyclic structure, featuring nuclear spin-free donors and additional possibilities for chemical functionalization, makes 1′ a new convenient spin-coherent building block in quantum technologies