Impact of Alginate and fluoroethylene carbonate on the electrochemical performance of SiO−SnCoC Anode for Lithium-Ion Batteries

X. ZENG; Z. CHEN; Y. LI; E. P. M. LEIVA; G. L. LUQUE; X. LUO; K. AMINE

Congreso; 3rd International Workshop on Lithium, Industrial Minerals and Energy; 2016

The demand of high quality, clean and mobile energy is increasing every day, making is necessary to have new renewable energy sources like wind power and solar power, which require a large scale energy storage system to handle the phase shift between the power generation and the consumption. In this regard, lithium-ion battery technology has become one of the most promising candidates, and it has already been used as power sources in modern portable electronics, hybrid electric vehicles and electric vehicles. In order to meet the demanding requirements for emerging applications in transportation system, it is necessary to develop lithium-ion devices with high power density, low cost, safe and long cycle/calendar life. Graphite has been the dominant anode material in commercial batteries, but it cannot meet the energy-density requirement, mainly because of its relatively low specific capacity. The materials that are showing greater promise than graphite are those metallic composites that can store lithium via alloying processes. In this regard SiO and Sn have high theoretical capacity and alloys of this materials show excellent specific capacity.The problem that faces these metallic composite materials is that they experience a large volume expansion and contraction during lithium uptake and release that induces cracking of particles, leading to the electrical isolation of the particles and the collapse of the composite electrode, both of which lead to the deterioration of the electrochemical reversibility. Recent studies have shown that use of alternative binders other than PVDF can improve the reversibility and the mechanical properties of the electrodes based on lithium alloying components. It has been reported that polymers that contain carboxylate and hydroxyl functional groups can effectively improve the cycling stability of Si-based electrodes.It is important to note, that not only the binder plays a key role in the electrochemical performance of the electrode and the formation of the solid electrolyte interphase (SEI), but also the additives in the electrolyte can also modify the chemical composition and distribution of SEI layer, and therefore, improve the electrochemical performance of the electrode. Thus, in the present article, we study the impact of Alginate as a binder. We also evaluate the effect of the incorporation of fluoroethylene carbonate (FEC) as additive in the electrolyte, which has proven to be one of the most effective additives not only for graphite based electrodes, but also for silicon based materials. It was found that both fluoroethylene carbonate and alginate binder help to improve the electrochemical stability of the composite anode. Particularly, the high precision self-discharge study revealed that the alginate binder slowed down the parasitic reactions between the lithiated anode and the non-aqueous electrolyte.