A layered Bi2Te3 nanoplates/graphene composite with high gravimetric and volumetric performance for Na-ion storage

Abstract

Exploring new electrode materials with both high gravimetric and volumetric Na-ion storage performances is urgently desired but still faces significant challenges. In this work, a composite of layered Bi₂Te₃ nanoplates/graphene, which is denoted as Bi₂Te₃/G, was synthesized by a one-pot solvothermal method. Here, Bi₂Te₃ nanoplates with a large interlayer spacing of 1.02 nm were uniformly anchored on graphene with strong interfacial interaction. The obtained Bi₂Te₃/G composite exhibited high reversible gravimetric capacity of 416 mA h g⁻¹ at 0.1 A g⁻¹ and an excellent rate performance. Even at 5.0 A g⁻¹, Bi₂Te₃/G still delivered a gravimetric capacity as high as 203 mA h g⁻¹. Due to its high tap density of 1.56 g cm⁻³, Bi₂Te₃/G also delivered impressive volumetric capacities. The reversible volumetric capacity was as high as 648.9 mA h cm⁻³ at 0.1 A g⁻¹. At 5 A g⁻¹, Bi₂Te₃/G still retained volumetric capacity of 316.7 mA h cm⁻³. The excellent gravimetric and volumetric Na-ion storage performances of the Bi₂Te₃/G composite should be ascribed to the quintuple layer sandwich structure of Bi₂Te₃, the synergistic effect between Bi₂Te₃ and graphene, and its higher density. Accordingly, the Bi₂Te₃/G composite is expected to exhibit great application prospects as a promising anode candidate for smart sodium-ion batteries.