Preparation Of MOF-based Silicon Anode By Cutting Silicon Waste And Its Lithium Storage Performanc

With the continuous increase of human demand for energy,traditional energy resources are gradually exhausted,and environmental pollution problems are becoming more and more serious.Therefore,the development of clean energy has become an area that countries around the world need to pay attention to and develop urgently.Among many clean energy sources,solar energy is attracting more and more attention due to its high efficiency,saving,convenient installation and suitability for wide-scale use.Among them,crystalline silicon solar cells are the most common type of cells in the solar cell market at present,but a large amount of silicon powder will be produced during the production of silicon wafers and will flow away with the cutting fluid,eventually forming silicon waste.With the rapid development of the photovoltaic industry,the generation of photovoltaic cutting silicon waste is also increasing.Therefore,finding an economical,environmentally friendly and safe method of processing photovoltaic cutting silicon waste has become one of the important issues facing the current solar cell industry.Based on the above,this project proposes the preparation of porous Si@MOF composite materials for the anode of lithium-ion batteries to realize the efficient recycling of SCW and provide a new idea for the green recycling of photovoltaic cutting silicon waste.The research results of this paper are as follows:（1）Low-cost photovoltaic cutting silicon waste is used as raw material,and ZIF-67 is synthesized in situ on its surface,and the submicron-scale porous cage-like silicon-based composite material is obtained by carbonization.When the current density is 200 m A g^-1,the initial discharge The capacity can maintain a high specific capacity of 2858.32 m Ah g-1,and even after 100 cycles,the negative electrode of Si@NC-ZIF can provide a high specific capacity,and the capacity retention rate is86.29%.After 200 long cycles at high current density,the discharge capacity of Si@NC-ZIF can be stably maintained at 1034.19 m Ah g^-1.When the scan rate is 1m V/s,the pseudocapacitive contribution to Li⁺storage reaches 85%,indicating that the Si@NC-ZIF electrode has excellent pseudocapacitive performance.（2）Electrochemical tests were performed at a current density of 500 m A g^-1.The initial discharge/charge specific capacity of the bimetallic Si@Co Cu-ZIF composite reached 2336.63/1903.6 m Ah g^-1,and its initial Coulombic efficiency was also obtained.81.4%,which is significantly higher than the single metal Si@NC-ZIF material.After a long cycle test of 1000 cycles,the reversible capacity still has a high value of1100.95m Ah g^-1,which is three times that of commercial graphite anodes currently on the market.And according to the electrochemical impedance spectroscopy,it can be seen that the charge transfer resistance is reduced from 189Ωto 80Ω,and the diffusion resistance of the electrode has also been greatly improved.