Construction Of Quinone Amine Polymer Organic Cathode Material And Their Zinc Ions Insertion/extraction Mechanism Research

Organic cathode materials are emerging energy storage materials for building safe and environmentally friendly aqueous zinc ion batteries（AZIB）,promoting their development and large-scale application conforms to the strategic needs of China’s new energy storage technology research.However,the electrochemical performance of organic cathode materials in AZIB are limited by low capacity utilization,rapid long cycle decay and other shortcomings,which are essentially due to the high charge and large radius of Zn²⁺,and the relatively weak force with organic functional groups result in low insertion/extraction efficiency.The three-dimensional space structures of organic cathode materials are complex,and the configuration of electrochemically active functional groups play key roles in the coordination ability with Zn²⁺,which directly affect the Zn²⁺insertion/extraction efficiency.Designing organic cathode materials with electrically active functional group configuration for synergistically coordinating Zn²⁺,and exploring the mechanisms of their configuration-controlled Zn²⁺insertion/extraction are important to improve the basic theory and establish universal design methods for high-performance organic cathode materials.In this paper,we design and synthesis four series of quinone-anime polymers as cathode materials,systematically investigate the Zn²⁺insertion/extraction mechanism and the structural relationship between molecular configuration and Zn²⁺insertion/extraction regulation,the details are as follows:A series of cathode materials:poly（1,4-benzoquinone-thiourea）（PQTU）,poly（1,4-benzoquinone-urea）（PQU）and poly（1,4-benzoquinone-ethylenediamine）（PQEDA）are synthesized.We systematically study their electrochemical performance and Zn²⁺insertion/extraction mechanism,and further research the mechanism for the polymerization chain groups’ability of coordinating Zn²⁺to modulate Zn²⁺insertion/extraction.The results show that the modification of polymer chains with coordination groups can promote Zn²⁺insertion/extraction,improving the capacity utilization rate and long-term cycling performance,the promotion effect is positively correlated with the Zn²⁺coordination ability of coordination groups.The thiourea groups in PQTU polymerization chain have the strongest coordination ability with Zn²⁺,exhibiting the best electrochemical performance,the maximum discharged specific capacity can reach 211 m Ah/g at 0.02 A/g and the long-term cycling retention can keep83%after 1000 cycles at 0.1 A/g.The ex-situ XPS and FTIR characterizations indicate that the thiourea groups on the polymer chain synergistically cooperate with the quinone carbonyl groups to coordinate with Zn²⁺,promoting Zn²⁺insertion/extraction and thereby improving electrochemical performance.Based on the auxiliary-coordination promotion strategy of Zn²⁺insertion/extraction,poly（1,4-benzoquinone-square amide）（PCSA）cathode material is designed and synthesized,its electrochemical performance and Zn²⁺insertion/extraction mechanism are systematically investigated.The squaramide auxiliary-coordination groups have ortho carbonyl rigid quaternary ring configuration,which are more stable to coordinate Zn²⁺,and can promote Zn²⁺insertion/extraction through the competition of coordination differences.At 0.02 A/g,the maximum discharged specific capacity is 188 m Ah/g,the capacity utilization is 98.4%and the capacity retention remains 93%after 400 cycles.At0.1 A/g,the capacity retention rate can still reach 80%after 1000 cycles.The ex-situ XPS and FTIR characterizations show that the squaramide auxiliary-coordination groups are involved in Zn²⁺coordination/decoordination during the charged/discharged process,which enhance the capacity utilization rate,promoting the Zn²⁺insertion/extraction,and exhibiting excellent electrochemical performance.Three kinds of cathode materials:poly（1,4-benzoquinone-1,2-benzenediamine）（PQO）,poly（1,4-benzoquinone-1,3-benzenediamine）（PQM）,and poly（1,4-benzoquinone-1,4-benzenediamine）（PQP）are designed and synthesized,which belong to the same series materials,their electrochemical performance and Zn²⁺insertion/extraction mechanism are systematically investigated,we further research the mechanism of Zn²⁺insertion/extraction regulation by the quinone carbonyl configuration of ortho quinone units.The results show that PQO,PQM,and PQP have the same theoretical specific capacity,but PQO exhibit much better electrochemical performance than PQM and PQP.PQO has discharged specific capacity of 186 m Ah/g at 0.02 A/g and the capacity retention remains 82%after 200 cycles,which is larger than these of PQM and PQP.The cooperative-coordination configuration is constituted by the quinone carbonyl C=O of ortho quinone units in PQO,which is more conducive to stabilize Zn²⁺insertion/extraction.The space during quinone carbonyls C=O of ortho quinone units is increscent in PQM,leading to the decrease of electrochemical performance.Whereas the quinone carbonyls C=O of ortho quinone units do not form the cooperative-coordination configuration in PQP,resulting the worst electrochemical performance.A series of cathode materials:poly（1,4-benzoquinone-1,4-diaminoanthraquinone）（PQN14）,poly（1,4-benzoquinone-1,5-diaminoanthraquinone）（PQN15）and poly（1,4-benzoquinone-2,6-diaminoanthraquinone）（PQN26）are designed and synthesized,the electrochemical properties and Zn²⁺insertion/extraction mechanism are systematically investigated,and we further research the mechanism of regulating Zn²⁺insertion/extraction by quinone carbonyl molecular configulation.Two quinone carbonyl groups in the ortho 1,4-benzoquinone and 1,5-aminoanthraquinone units can form synergistic coordination configuration to coordinate Zn²⁺in PQN15,stabilizing the Zn²⁺insertion/extraction and exhibiting the best performance.The discharged specific capacity of which is 237 m Ah/g at 0.02 A/g and the capacity retention remains 96%after 600cycles,the capacity retention remains 87%and 94%at 0.1 A/g and 1 A/g after 2000long-term cycles,respectively.Two quinone carbonyl groups in the ortho1,4-benzoquinone and 1,4-aminoanthraquinone units can also form synergistic coordination configuration to coordinate Zn²⁺in PQN14,however,the stability of Zn²⁺insertion/extraction is reduced due to the group effect of the same side substitution of its anthraquinone unit,resulting the decrease of electrochemical performance.Besides,the distance between the two quinone carbonyl groups in the 1,4-benzoquione and2,6-aminoanthraquinone units are relatively far in PQN26,they cannot form synergistic coordination configuration,resulting the worst electrochemical performance.