Lithium Nitridonickelate As Anode Coupled with Argyrodite Electrolyte for All-Solid-state Lithium-Ion Batteries

Argyrodites Li6PS5X (X = Cl, Br) have attracted growing interest due to their exceptional ionic conductivity and ductility, making them promising electrolytes for all-solid-state lithium-ion batteries. However, their poor electrochemical stability at very low potential limits the use of lithium metal as a negative electrode. Instead of using Li-In alloy, this study explores the electrochemical properties of lithium nitridonickelate Li2.07Ni0.62N as an alternative negative electrode material, paired with balled milled argyrodite Li6PS5Br. The same electrochemical storage mechanism observed in liquid media is at work here, exhibiting a solid-solution profile along with low lattice expansion through the reversible insertion mechanism. By adjusting the potential window to minimize argyrodite degradation, the active material delivered a stable capacity of 125 mAh g_ 1 over 60 cycles at C/25, with a mean working potential of 0.5 V at room temperature. The excellent capacity retention was achieved up to C/10, demonstrating good compatibility between the argyrodite solid electrolyte and lithium nitridonickelate negative electrode.