Preparation Of Carbon Black And Biomass-Based Hard Carbon Composites And Application Of Lithium/Sodium Storage Performance

Lithium-ion batteries(LIBs)have become the primary energy storage system in the fields such as electronic equipment,electric vehicles and grid storage,due to their green environmentally-friendliness and no memory effect.Anode materials are an essential part of lithium-ion batteries.Traditional graphitic materials can no longer meet the requirements of battery anode materials.Therefore,the development of advanced anode materials is of high importance for the development of LIBs.On the other hand,the limitation and uneven distribution of lithium resources will not be able to meet the energy storage needs of large-scale lithium-ion batteries in the future.Sodium,as a possible alternative,has abundant resources and lower costs compared to lithium.Therefore,the development of sodium-ion batteries(SIBs)is highly important.However,the Na⁺radius(0.102 nm)is larger than that of Li⁺(0.076 nm),which leads to unstable sodium-graphite thermodynamics;commercial LIBs graphite anode performs poorly in SIBs.Therefore,the development of a high-performance and low-cost alternative anode material is crucial to the development of SIBs technology.Among the many anode materials,hard carbon(HC)has become one of the most promising anode materials for lithium/sodium ion batteries because of its low average potential,high electrochemical activity,and relatively low cost.In order to develop a superior hard carbon anode material for lithium/sodium ion batteries,this paper selects low-cost carbon black and eggplant biomass carbon as precursors,by combining carbon black and metal oxides,and eggplant biomass carbon and heteroatoms doping.Herein,we have successfully prepared a series of hard carbon-based materials with excellent electrochemical performance.The authors first prepared carbon black/Fe₃O₄ hard carbon-based composites by mixing carbon black with ferric chloride hexahydrate as a precursor.The study investigated the effects of carbonization temperature,the ratio of carbon black and ferric chloride hexahydrate on the structure and electrochemical performance of carbon black/Fe₃O₄ hard carbon-based composites.The research results show that carbon black/Fe₃O₄ hard carbon-based composite materials without other iron impurities are prepared at a carbonization temperature of 700°C,and when the ratio of carbon black and ferric chloride hexahydrate is 1:3,the material has a higher The specific capacity and good cycle stability can provide a reversible capacity of 404.1m Ah/g at a current density of 0.1 A/g,which is much higher than the capacity of raw carbon black and commercial Fe₃O₄.Also,eggplant was used as a carbon source,which was activated by calcium chloride and doped with urea to prepare a high specific surface area nitrogen-rich biomass hard carbon material.This study investigated the effects of carbonization temperature,calcium chloride and urea addition on the structure,morphology,and lithium/sodium storage performance of the synthesized biomass hard carbon material.It is determined that when the carbonization temperature is 800°C and the biomass precursor:Ca Cl₂:urea=1:2:2,the prepared biomass hard carbon material has the best sodium storage performance,at a current density of 0.1 A/g It can provide a reversible capacity of 200.8 m Ah/g,and at a current density of 2 A/g,it still has a reversible capacity of 137.8 m Ah/g after1000 cycles;When the carbonization temperature is 900°C and the biomass precursor:Ca Cl₂:urea=1:2:2,the prepared biomass hard carbon material has a reversible lithium storage capacity of 920.7 m Ah/g after 100 cycles at the current density of 2A/g.