Lithium argyrodite thiophosphate superionic conductors are being explored as promising solid electrolytes for all-solid-state batteries, primarily due to their high ionic conductivity and ease of processing. Yet, these electrolytes present challenges such as chemical instability in humid conditions and incompatibility with cathode materials. Although some lithium argyrodites show improved air stability, their ionic conductivity deteriorates below the practically required value. Herein, based on hard soft acid base theory, a new family of lithium argyrodite, as solid solution Li6−xAsS5−xBr1+x (for 0.0 ≤ x ≤ 0.6), has been proposed to address these issues. Through a combination of neutron diffraction, NMR spectroscopy, and electrochemical impedance spectroscopy, it has been determined that the partial substitution of S2− by Br− weakens interactions within the Li+ “cage”, facilitating long lithium-ion movement throughout the structure. An additional T4 Li+ site is identified, offering a lower energy barrier for inter-cage jumps. Consequently, the Li5.5AsS4.5Br1.5 member of the composition series exhibits a higher Li-ion diffusivity resulting in a remarkable ionic conductivity of 15.4 mS cm−1. Compared with lithium thiophosphates, the Li5.5AsS4.5Br1.5 also shows excellent air stability. This research opens a new avenue for developing air-stable sulfide solid electrolytes with high ionic conductivity necessitated for practical application in solid-state batteries.@en

Lithium argyrodite solid electrolytes have attracted ever-increasing attention for all-solid-state batteries due to their high ionic conductivity and low cost. However, the relation between structure and ionic transport for the halogen-rich lithium argyrodites under different synthesis routes is still elusive. Herein, the influence of synthesis procedures, such as annealing conditions and balling milling, on the structure, ionic conductivity, and activation energy of the lithium argyrodite (e.g., Li_5.5PS_4.5Cl_1.5, Li_5.3PS_4.3Cl_1.7), is systematically investigated. Compared with high-energy ball milling followed by annealing, using fast dry mixing followed by annealing can obtain comparable ionic conductivity of the chlorine-rich lithium argyrodites. Single-crystal LiNi_0.83Co_0.11Mn_0.06O₂-based solid-state battery with these electrolytes shows stable cycling performance, demonstrating that chlorine-rich lithium argyrodite is a promising candidate for all-solid-state batteries.

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N-type microcrystalline silicon carbide (μc-SiC:H(n)) is a wide bandgap material that is very promising for the use on the front side of crystalline silicon (c-Si) solar cells. It offers a high optical transparency and a suitable refractive index that reduces parasitic absorption and reflection losses, respectively. In this work, we investigate the potential of hot wire chemical vapor deposition (HWCVD)–grown μc-SiC:H(n) for c-Si solar cells with interdigitated back contacts (IBC). We demonstrate outstanding passivation quality of μc-SiC:H(n) on tunnel oxide (SiO₂)–passivated c-Si with an implied open-circuit voltage of 742 mV and a saturation current density of 3.6 fA/cm². This excellent passivation quality is achieved directly after the HWCVD deposition of μc-SiC:H(n) at 250°C heater temperature without any further treatments like recrystallization or hydrogenation. Additionally, we developed magnesium fluoride (MgF₂)/silicon nitride (SiN_x:H)/silicon carbide antireflection coatings that reduce optical losses on the front side to only 0.47 mA/cm² with MgF₂/SiN_x:H/μc-SiC:H(n) and 0.62 mA/cm² with MgF₂/μc-SiC:H(n). Finally, calculations with Sentaurus TCAD simulation using MgF₂/μc-SiC:H(n)/SiO₂/c-Si as front side layer stack in an IBC solar cell reveal a short-circuit current density of 42.2 mA/cm², an open-circuit voltage of 738 mV, a fill factor of 85.2% and a maximum power conversion efficiency of 26.6%.

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