Conventionally, materials in this category are characterized by a single conduction layer. However, their work has yielded a particularly intriguing material, namely Ag 6 M 2 TeO 6 (where M can represent Ni, Mg, or other transition metal atoms), which exhibits a distinctive structure featuring bi-layers of Ag atoms within Ag-rich crystalline domains, as depicted in Fig. (i) . This bi-layer-type honeycomb layered oxide configuration represents a unique and novel structural motif.