Design And Preparation Of Nanoporous Germanium-based Composites And Study On Their Lithium Storage Performance

With the increasingly serious environmental pollution and energy crisis,people urgently need a new generation of energy storage equipment to replace traditional fossil fuels to alleviate the energy storage crisis.Lithium-ion batteries?LIBs?have attracted much attention in the field of energy storage due to their high energy density,long cycle life,and environmental protection without pollution.Unfortunately,due to the low theoretical capacity of graphite-based anode materials,the increasing energy demand has not been met.Researchers are actively looking for anode materials with high theoretical capacity and excellent cycle performance.IVA group elements are considered to be the most promising anode materials due to their high theoretical capacity,but the huge volume expansion during the deintercalation of lithium causes its structure to collapse and pulverize,which seriously affects cycle stability.Based on the above problems,the design and preparation of germanium-based nanoporous structures,and the introduction of rigid materials with excellent conductivity and a small volume expansion rate that can significantly suppress volume expansion,all of these strategies can alleviate the large volume change and poor conductivity of germanium groups.In this paper,a nanoscale three-dimensional interconnected channel structure germanium-based composite material is prepared by using arc melting furnace melting and high-vacuum spin-quenching system stripping and mild selective etching.The germanium-based nanocomposite material prepared by this wet-chemical method shows excellent electrochemical performance when used in a lithium battery negative electrode.The main content of this article:1.Combined with ternary phase diagram analysis,GeCuAl,GeTiAl and GeAgAl ternary alloys with uniform and controllable composition were designed and prepared.Select appropriate etching conditions to etch more active aluminum atoms with chemical properties,and obtain three-dimensional interconnected nanopore structures,such as nanoporous Ge/Cu₃Ge,Ge@TiO₂,Ge/Ag composite materials.2.Characterize the structure and morphology of the prepared nano-porous Ge/Cu₃Ge,Ge@TiO₂,Ge/Ag composites.According to SEM and TEM characterization,it can be seen that the eroded composite material is composed of three-dimensional interconnected channel structures.The channel structure is composed of the main germanium-based bone spine ligament and the modified metal and its oxide.The analysis shows that the material composition after the corrosion is uniform and the content is controllable.3.Further perform electrochemical performance tests.Due to the introduction of modified metals and their oxides,the germanium-based materials after compounding all show excellent capacity,excellent cycle performance,and outstanding rate performance.The germanium-based composite material prepared by the de-alloying method has a simple preparation method and excellent electrochemical performance,and has wide application potential in the field of energy storage.