Preparation Of Main Group Metal Chalcogenide Compound And Their Lithium Storage Performance

Lithium-ion batteries play an important role in our lives.However,their energy density has become increasingly difficult to meet the rapidly growing needs of our society.Therefore,there is an urgent need to develop higher capacity electrode materials.Among many anode materials,the main group metal chalcogenide compounds have attracted tremendous attention as anode materials for lithium-ion batteries due to their relatively high capacity,suitable potential and large bulk capacity density.However,metallic chalcogenide compounds usually suffer from problems such as low electrical conductivity and huge volume change,which seriously hinder their application.In this paper,from the synthesis and structural design of high specific capacity indium selenide and aluminum sulfide materials,respectively,with the concept of nanostructure design and interface modulation to improve their electrochemical performance.We have constructed multi-yolk-shell In₂Se₃@C nanospheres and ultrafine Al₂S₃nanocrystals anchored on two-dimensional carbon sheets,respectively.Moreover,their electrochemical lithium storage performance was studied in detail.1.Glucose-coated solid In（OH）₃ nanospheres（In（OH）₃@G）were firstly prepared,followed by the conversion of In（OH）₃@G into multi-yolk-shell In@C nanospheres using the effect of volume contraction upon the reduction of In（OH）₃ by heating.Finally,the multi-yolk-shell In₂Se₃@C nanospheres with multiple In₂Se₃ nanoparticles inside have been successfully synthesized and constructed by chemical vapor phase selenization.The theoretical calculation results show that this multi-yolk-shell structure not only enhances the adsorption of Li atoms（In₂Se₃@C:-2.95 e V,In₂Se₃:1.92 e V）but also reduces the diffusion barrier of Li ions,resulting in improved electrical conductivity,Li ions diffusion process and structural stability of In₂Se₃.In addition,the carbon shell can effectively buffer the volume expansion of In₂Se₃ particles and ensure full contact of In₂Se₃-carbon shell interface,which provides more ion/electron transport channels and significantly promotes the electrochemical reaction kinetics and improves the material cycling stability.Thus,multi-yolk-shell In₂Se₃@C electrode exhibits high reversible capacities and remarkable cycling stability,delivering a stable capacity of 800 m Ah g^-1 after1000 cycles at1000 m A g^-1.2.Al₂S₃/C nanocomposite was synthesized using a high-energy mechanical ball milling method.This method not only effectively achieves the uniform composite of Al₂S₃nanoparticles and carbon sheets,but also successfully controls Al₂S₃ into ultrafine nanocrystals.Al₂S₃/C electrode demonstrates very outstanding lithium storage performance with large reversible specific capacity(1249 m Ah g^-1 at 100 m A g^-1),remarkable rate capability(670 m Ah g^-1 at 5000 m A g^-1)and superior long-cycling stability(retaining 850 m Ah g^-1 even after 1000cycles at 1000 m A g^-1).Moreover,the reversible lithium storage behavior and excellent diffusion kinetics of Al₂S₃/C are deeply unveiled.This work provides an inspiration to develop new light metal sulfide materials for the next-generation high-performance lithium-ion battery.