Preparation Of Carbon/Aluminum Composite Collector And Their Application In Lithium Battery

Lithium batteries,with the advantages of high energy density,long lifespan,light weight,and low cost,are widely used in electric vehicles,commercial energy storage,electronic products and power generation equipment.As an important component of lithium batteries,current collectors play an important role in communicating external circuits with internal electrochemical reactions,and has a significant impact on the performance of lithium batteries.Improving the conductivity of the current collector,reducing contact resistance,and enhancing electrochemical corrosion resistance are crucial for enhancing the specific capacity,rate capacity,efficiency,and cycle stability of lithium batteries.Aluminum is a lightweight,conductive,durable,and electrochemically stable material,suiting as the cathode current collector for fabricating high energy density lithium batteries.At present,the cathode current collector of commercial lithium batteries is aluminum foil,which electrochemical stability mainly comes from the dense aluminum oxide protective layer on the surface of aluminum foil.However,aluminum foil current collector is susceptible to local electrochemical anodic corrosion during long-term battery cycling,resulting in increased resistance,short circuits and parasitic side reactions,and then leading to issues such as battery performance degradation,failure,and reduced service life.Therefore,there is an urgent need to develop new aluminum-based composite current collector materials with high stability,conductivity,bonding strength,lightweight,and low cost.In order to solve the above problems,two vacuum deposition technologies including magnetron sputtering and magnetic filtration multi arc ion plating are used to deposit conductive carbon layer on the surface of aluminum foil to prepare carbon/aluminum composite collector materials for the fabrication of lithium batteriers with high specific capacity and high cycle stability.The main research results of this article are as follows:（1）The conductive carbon layer was successfully deposited on the surface of aluminum foil by magnetron sputtering method to prepare novel carbon/aluminum composite current collector.By adjusting the surface treatment method,transition layer deposition time,substrate bias voltage and carbon layer deposition time in the process,the adhesion,conductivity and electrochemical corrosion resistance of carbon/aluminum composite current collector are optimized.The carbon/aluminum composite current collector,prepared by plasma cleaning and deposition of a5-minute aluminum transition layer,with a substrate bias voltage of 40 V and a carbon layer deposition time of 1 hour,exhibited optimized adhesion,conductivity,and electrochemical corrosion resistance.Furthermore,a lithium battery device based on the as-prepared carbon/aluminum composite current collector was fabricated.Compared to the devices based on the commercial aluminum foil material,the lithium battery device with carbon/aluminum composite current collector have a significant improvement in specific capacity and cycle stability.The specific capacity of lithium battery devices prepared by using carbon/aluminum composite current collectors can reach 108.9 m Ah g^-1at a high current density of 10 C.After 300 cycles at a current density of 1 C,its specific capacity can still maintain 97.5%.（2）A conductive carbon layer was successfully deposited on the surface of aluminum foil by using magnetic filtration multi arc ion plating method to prepare novel carbon/aluminum composite current collector material.By optimizing the substrate bias during the coating process,we prepared a carbon/aluminum composite collector with high density,high bonding strength,high conductivity and high electrochemical corrosion resistance.We constructed a lithium battery device with high specific capacity and long cycle stability using a carbon/aluminum composite thin film prepared at a bias voltage of 150 V as the current collector.The specific capacity of the device can reach 112.1m Ah g^-1at a high current density of 10 C.After cycling for 300 cycles at a current density of 1 C,its specific capacity can still maintain 97.0%.