SnO <sub>2</sub> quantum dots modified N‐doped carbon as high‐performance anode for lithium ion batteries by enhanced pseudocapacitance
Cuiping Wu, Kaixuan Xie, Jiapeng He, Qingpeng Wang, Jian‐Min Ma, Shun Yang, Qinghong Wang
Abstract
Abstract 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.