SnO2 quantum dots modified N-doped carbon as high-performance anode for lithium ion batteries by enhanced pseudocapacitance

SnO 2 is considered to be a promising candidate as anode material for lithium ion batteries, due to its high theoretical specific capacity (1494 mAh·g −1 ). Nevertheless, SnO 2 -based anodes suffer from poor electronic conductivity and serious volume variation (300%) during lithiation/delithiation process, leading to fast capacity fading. To solve these problems, SnO 2 quantum dots modified N-doped carbon spheres (SnO 2 QDs@N–C) are fabricated by facile hydrolysis process of SnCl 2 , accompanied with the polymerization of polypyrrole (PPy), followed by a calcination method. When used as anodes for lithium ion batteries, SnO 2 QDs@N–C exhibits high discharge capacity, superior rate properties as well as good cyclability. The carbon matrix completely encapsulates the SnO 2 quantum dots, preventing the aggregation and volume change during cycling. Furthermore, the high N content produces abundant defects in carbon matrix. It is worth noting that SnO 2 QDs@N–C shows excellent capacitive contribution properties, which may be due to the ultra-small size of SnO 2 and high conductivity of the carbon matrix. Graphic abstract SnO2 quantum dots modified N-doped carbon spheres are successfully fabricated by facile hydrolysis-high temperature calcination approach using SnCl2 and pyrrole monomer as precursors. As anodes for lithium ion batteries, the SnO2 QDs@N-C-600 exhibits superior rate capability and excellent cycling stability. This work provides an effective way to obtain electrode materials with high specific capacity and good cycling performance for energy storage