Research On The Application Of Nitrogen-containing Organic Electrode Materials In Dual Ion Batteries

Lithium-ion batteries(LIBs)can not satisfy the ever-growing demands due to these shortcomings such as the scarce lithium resources,expensive cathode materials,and limited theoretical capacity of graphite anode materials.Dual-ion batteries(DIBs)have attracted widespread attention due to their low cost,environmental friendliness,and high operating voltage.Currently,the DIBs using inorganic materials as cathode and anode materials have the disadvantage of unsustainability.Compared with inorganic materials,organic electrode materials have some advantages,such as the simple synthesis method,low consumption,and recyclable or degradation treatment.Therefore,it can be seen that organic materials have the advantages of sustainable development,low cost and environmental friendliness.Among them,the nitrogen-containing organic electrode material has good electrochemical performance.Thus,we synthesized a series of nitrogen-containing organic compounds and studied their electrochemical performance as electrode materials for DIBs.The specific research contents were as follows:(1)A series of phthalocyanine derivatives were designed and synthesized.The comparison results showed that copper tetraaminophthalocyanine(Cu TAPc)exhibited the best electrochemical performance due to its bipolar and self-polymerizing properties.Based on the bipolar characteristics,Cu TAPc can be assembled into different types of batteries.When DIBs half-cells were assembled with lithium,the Cu TAPc cathode material shows excellent cycling performance,and after 4000 cycles at a large current density of 4 A g-1,it still maintained a high reversible capacity of 74.3 m Ah g-1.When asymmetric DIBs were assembled with graphite,Cu TAPc can exhibit an initial charge and discharge capacity of 287.11/208.1 m Ah g-1 at a current density of 0.3 A g-1.When symmetrical all-organic DIBs were assembled,the initial charge and discharge capacity was 133.2/110.9 m Ah g-1 at a current density of 0.2 A g-1,which can provide a high energy density of 239 Wh kg-1 and a high-power density of 11.5 k W kg-1.(2)A metal-organic framework(Cu TCNQ)was designed and synthesized.Cu TCNQ was used as the anode material and graphite was used as the cathode material.Lithium-based dual-ion(LDIBs)and sodium-based dual-ion batteries(SDIBs)were assembled,and both them showed good electrochemical properties.The initial discharge specific capacity of LDIBs at a current density of 0.1 A g-1 was 190.8 m Ah g-1.After 100 cycles,the capacity had no obvious attenuation.At the same time,it showed good rate performance,at the current density of 5 A g-1,it still had the discharge specific capacity of 106.2 m Ah g-1.SDIBs had a discharge voltage of 4.23 V,and provided a discharge capacity of 76 m Ah g-1 at a current density of 0.1 A g-1.After 200 cycles,the reversible capacity was retained at 48 m Ah g-1.(3)A covalent triazine framework(CTF-1)based on terephthalonitrile was designed and synthesized,which showed a microporous structure and a high specific surface area of 956 m2 g-1.And a DIBs half-cell was constructed using the CTF-1 cathode material and lithium.After 100 cycles at a current density of 0.1 A g-1 under a voltage window of 1.5-4.5 V,the reversible capacity was retained at 120 m Ah g-1 with a capacity retention rate of 84.5%.Then,a DIBs full cell was constructed using the CTF-1 as cathode material and graphite as anode material,which showed good cycling performance.After 300 cycles at a current density of 100 m A g-1,there was no attenuation in capacity.