Self-assembled CoS2 nanoparticles wrapped by CoS2-quantum-dots-anchored graphene nanosheets as superior-capability anode for lithium-ion batteries

• DOI: 10.1016/j.electacta.2015.09.131
• Publication Date: 2015-09-29T22:42:15Z
• Authors: Jiarui He; Yuanfu Chen; Pingjian Li; Fei Fu; Zegao Wang; Wanli Zhang
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract For the first time, self-assembled CoS 2 nanoparticles wrapped by CoS 2 -quantum-dots anchored graphene nanosheets (CoS 2 NP@G-CoS 2 QD) are synthesized by a facile l -cysteine-assisted hydrothermal reaction. When the composite is used as anode in lithium-ion batteries (LIBs), it shows superior electrochemical performance: the reversible specific capacity is as large as 1048 mAh g −1 ; the 300 th -cycle capacity still maintains 831 mAh g −1 even at 1 A g −1 ; the rate capacity remains 411 mAh g −1 even at 10 A g −1 , which is the highest value ever reported at such high current density for CoS 2 based materials. The excellent electrochemical performance is attributed to the unique structure with CoS 2 nanoparticles homogeneously wrapped by highly flexible and conductive few-layer graphene nanosheets adhering abundant CoS 2 quantum dots, which can effectively suppress the aggregation of CoS 2 nanoparticles, accommodate the volume change during the cycle processes and maintain high electrical conductivity of the electrode. The CoS 2 NP@G-CoS 2 QD composite is promising for superior-capability anode for LIBs and can be further extended to broad applications in supercapacitors, sensors, and catalysis.