Side reaction and modification strategy of perfluoro electrolytes with Si/C anode
Fluoroethylene carbonate (FEC) is a popular additive for Li-ion battery,which can improve long-cycle stability. However,when the addition of FEC in the electrolyte exceeds 10％ of mass fraction,it can lead to severe gas production,which causes safety hazards to the battery and affects the lifetime of battery.The gas generation and interfacial side reactions of SiOx/graphite (Si/C) anode are researched using 1 mol/L lithium difluoro-oxalate borate (LiDFOB)/FEC as the base electrolyte,and polyurethane (PU) is introduced to alleviate side reactions between Si/C anode and the electrolyte.The decomposition of FEC on the anode surface continues to generate CO2 and H2 .The volume expansion of Si/C anode is suppressed with the addition of PU,which can inhibit the rupture and reconstruction of solid electrolyte interface (SEI) film,avoid the contact between FEC and anode,thus alleviate the interface side reactions and the electrochemical performance of the electrolyte is improved.The Li|Si/C battery can be stably cycled for 200 times at a rate of 0.5 C in 0.001-1.500 V,the capacity retention rate is 74.98％.
Li-ion batteryelectrolyteperfluoro electrolyteSi/C anodefluoroethylene carbonate(FEC)polyurethane (PU)interface side reaction
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