Preperation And Electrochemical Properties Of Silicon-based Electrode Materials For Lithium-ion-battery

To meet the develop of the times,Lithium-Ion-Battery(LIB),one of the most epidemical energy device,facing the problems urged to be solved including improving the specific capacity,cutting costs and simplifying the production process.As the second largest content chemical element in globe,elementary and oxide silicon are both showing high capacity combining with lithium and low discharge platform which considered to be an optical anode material in LIB.The theoretical specific capacity of elementary silicon is as high as 4200 m Ah/g and more than ten times of commercial graphite(372 m Ah/g).Its discharge platform lies in 0.2V.Drastic volume variation during repeated insertion and extraction with lithium ion result in remarkable capacity fading.Herein,a novel Si@void@C nano-architecture is obtained by using dopamine hydrochloride as the source of carbon.With the existence of amorphous carbon,elementary silicon can avoid contacting with electrolyte directly,and the void between carbon and elementary silicon provide space for its expanding during insertion lithium ion.Comparing to previous work,the novel nano-architecture is obtained by a less steps with a close performance.Similarly,the theoretical specific capacity of silica reaches up to 1965 m Ah/g,which is also several times of commercial graphite,and the discharge platform of silica lie in 0.1V-0.7V.Thougu the expand of volume during discharge is not as obviously as silicon,the poor electrical conductivity makes it hard to react with lithium ion not thoroughly,which leads to extremely low specific capacity.Here a Si O2@C nano-composite is obtained by popular hydrothermal reaction and using glucose as the source of carbon.Carbon coating on the silica nano-sphere serve as bridge for lithium ion transferring enhanced the conductivity of electrode materials,further advanced the capacity of Si O2 anode materials.By comparing with varies of anode materials differing from the content of carbon based on silica,a strong evidence is shown that more content of carbon provide better conductivity,and smaller particle makes capacity higher.