High lithium anodic performance of reduced Sn particles on Co metal-organic frameworks for lithium-ion batteries with a long-cycle life

Abstract

In recent years, lithium-ion batteries (LIBs) have become the battery technology of choice for portable devices, electric vehicles and grid storage due to their superior electrochemical performance and portability. Despite the successful commercialization of lithium-ion batteries in portable electronic devices, intensive research on high- energy density anode materials for lithium ion batteries is still ongoing to meet the ever-increasing high energy demand for upcoming advanced self-powering smart portable electronics and large-scale applications ranging from electric vehicles to power grids. In this regard, Surfactant-assisted cobalt metal-organic framework is synthesized through a solvo-thermal method and after Sn deposition uses as an anode in lithium-ion batteries. Using PEG400 resulted in a MOF with different trigonal (rhombohedral) lattice while a monoclinic structure is obtained when no surfactant is used. The presence of PEG400 polymeric surfactant with its role of orientation leads to the creation of special structural order and creates an array of structural units with a trigonal network (rhombone), which is completely different from the composition, creates in the same synthesis conditions with monoclinic structure. Different electrochemical behavior toward lithium insertion/extraction is attributed to different atomic packing factor. The trigonal structure synthesized at the presence of PEG400 shows better electrochemical performance compared to MOF1 at the absence of surfactant. Discharging capacity of the trigonal structure in the first cycle is about 615 mA h.gr 1 , which is increased by 3% in the second cycle and reaches 634 mAhgr 1 . Also, the amount of discharging capacity in 207 cycles is reduced to about 400 mAhgr 1 , which results in approximately twice the electrochemical performance of the pure tin and tin-cobalt alloy synthesized anodes by the electrochemical method and also indicates superior electrochemical performance in comparison with common graphite anodes.