Sn/SnOx/C复合纳米材料作为钠离子电池负极材料的研究

Research on Sn/SnOx/C Nanocomposites as Anode Material of Sodium Ion Battery

锡由于其低电位和高储钠理论容量以及绿色无毒的优点被认为是最有前途钠离子电池负极材料之一。但锡在嵌/脱钠的过程中会发生巨大体积膨胀,电极材料结构受到破坏,从而导致电池的容量和循环稳定性等电化学性能下降。本文提出了使用简单的一步水热法合成法制备锡及其氧化物和碳复合纳米材料(Sn/SnO_(x)/C)。该结构由被封装在连续碳薄层的纳米球组成,纳米结构可以缩短Na^(+)传输距离,碳网络除了可以有效提高材料导电性这外,还能减缓材料在脱/嵌钠过程的体积膨胀。电化学测试结果表明这种材料在0.15C的电流下可逆容量约为372 mAhg^(-1),在经过50个循环之后为344 mAhg^(-1),容量保持率约为92.2%,表现出良好的循环稳定性和电化学稳定性。

Sn is considered to be one of the most promising SIBs anode materials due to its high theoretical capacity,lower potential,environmental-friendly and non-toxic.But in the process of sodiation/desodiation,volume expansion will occur,resulting in the battery capacity and cycle stability and other electrochemical performance degradation.Sn/SnO_(x)/C nanocomposites were prepared by a simple one-step hydrothermal synthesis method.The nanostructure is composed of nanospheres encapsulated in a continuous carbon thin layer.The nanostructure can shorten the transmission distance of Na^(+),and the carbon network can effectively improve the electrical conductivity of the material,at the same time,it can slow down the volume expansion of the material in the process of sodiation/desodiation.The electrode retains a discharge capacity of 372 mAhg^(-1) and maintains 344 mAhg^(-1) after 50 cycles at a 0.15 C rate.The capacity retention rate was about 92.2%.These results show good cycle stability and electrochemical stability.