SnO_(2)@C/还原氧化石墨烯的制备及其作为锂离子电池负极材料的性能

Preparation of SnO_(2)@C/Reduced Graphene Oxide Nanocomposite as Anode Materials for Lithium-Ion Battery

SnO_(2)作为锂离子电池负极材料,因其储量丰富、放电电位低(小于1.5 V)、理论容量高等优点而被广泛研究。然而,SnO_(2)的电导率差,且在锂离子脱嵌过程中会产生巨大的体积膨胀(300%),导致其倍率性能和循环稳定性差,限制了其实际应用。以SnCl_(2)、L-抗坏血酸和氧化石墨烯(GO)作为反应物,采用一步水热法制备了SnO_(2)@C/r GO纳米复合材料。由L-抗坏血酸缩聚成的无定形碳可作为间隔剂有效抑制石墨烯(r GO)片层间的堆积,且可作为胶合剂将Sn O_(2)纳米颗粒锚定于rGO片层之上,有效提高了电极的循环稳定性。在电流密度为0.1 C(1 C=783 mA/g)时,180次循环后容量为731 mA·h/g,在5 C的大电流下可逆容量达410 mA·h/g。上述研究结果为高性能SnO_(2)负极材料的制备提供了新的科学途径。

SnO_(2)is widely investigated as one of anode materials for lithium-ion batteries due to its natural abundance,low discharge potential(less than 1.5 V)and high theoretical capacity.However,the low electrical conductivity and large volume expansion(300%)during Li+insertion/extraction results in the poor cyclability and rate capability of SnO_(2),thus restricting its practical applications.In this study,SnO_(2)@C/rGO nanocomposites were prepared by an one-step hydrothermal method with SnCl_(2),L-ascorbic acid and GO as reactants.The L-ascorbic acid-derived amorphous carbon served as a spacer to inhibit the stacking of rGO sheets and acted as a coupling agent to strongly anchor SnO_(2)nanoparticles on the r GO sheets.The as-obtained SnO_(2)@C/r GO nanocomposite delivers a specific capacity of 731 mA·h/g after 180 cycles at a current density of 0.1 C(1 C=783 mA/g)and a high reversible capacity of 410 mA·h/g at a large current rate of 5 C.This study provides a promising route for the preparation of high-performance SnO_(2)anode materials.