Performance And Research Of Phenolic Resin-based Carbon Materials As Electrode Materials

The development of new electrochemical energy storage technologies for using clean renewable energy is a vital way to solve energy shortages.Sodium-ion batteries lacking of suitable anode material can be applied in large-scale energy storage due to its low cost and abundant resources.Hard carbon material is considered to be the most potential anode materials for sodium ion batteries.However,its performance needs to be further improved to meet the needs of industrialization,and the mechanism of sodium storage of hard carbon materials is still controversial and needs further study.Supercapacitors have become the focus of many scholars because of high power density and long cycle life,but low energy density blocks their large-scale application.Increasing the specific capacitance of activated carbon electrode materials to increase the energy density of supercapacitors is a research hotspot.In this paper,the phenolic resin was synthesized using a resorcinol formaldehyde raw material system,and a series of hard carbon materials were obtained after treatment at different carbonization temperatures.The hard carbon material carbonized in 1300 ? have a reversible sodium storage capacity of 407 mAh/g,a initial coulombic efficiency of 88%,and a capacity retention rate of 89.8%after a cycle of 100 mAh/g current density for 200s.This material has a capacity of 372 mAh/g in a sodium ion full cell.At the same time,the hard carbon materials obtained by different carbonization temperatures were analyzed by using ex suit XRD,differeint scan rate CV,HTEM,Raman and outer test methods to summarize the relationship between structure and sodium storage performance.The plateau capacity is attribute to the Na+interaction in graphite-like microcrystal layers reversibility and slop capacity result from Na+ storage in defect.The La is the major factor of Na+storage capacity but the d002 mainly affect the intercalation voltage.The appropriate increase of the crystal parameter La of graphite-like microcrystals is conducive to the increase of the platform capacity,while there is an extreme value,and the capacity of the platform segment increased by La remains unchanged after reaching this value;The value of d002 mainly affects sodium-embedded voltage,and the larger value of d002 means the higher sodium-embedded voltage,while the smaller value of d002 means the lower sodium-embedded voltage.Activated carbon materials with graded pore structure were prepared by carbonization and activation of two-step synthetic resorcinol formaldehyde resin to explore the effect of activated alkali-carbon ratio on material properties.Wherein,when the alkali-carbon ratio is 4:1,the capacitance retention rate of the material with a high specific capacitance of 188.2 F/g is 85.8%after 5,000 cycles under the current density of 1A/g.When the alkali-carbon ratio is 5:1,the material has a good power characteristic and a capacity retention rate of.73.5%under the current density of 10A/g.