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 Li_2.07Ni_0.62N 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.