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

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.