【作者】 王浩；

【导师】 孙旦； 张旗；

【作者基本信息】 中南大学 ， 应用化学， 2024， 硕士

【摘要】 水系锌离子电池因锌金属天然丰度高、成本低、安全性高等优势在大规模储能领域具有极大应用前景。然而锌负极-电解质界面存在的析氢、腐蚀等副反应和锌枝晶生长等问题严重限制了电池的循环寿命,阻碍了锌离子电池的实用化进程。本文聚焦于电池内外因素对负极-电解质界面反应环境的影响及锌剥离/沉积行为的改变,基于添加剂优化电解液策略和电磁耦合效应,提出了三种可稳定锌负极提升电池性能的有效方案,深入探究相关作用机制。具体工作如下:（1）设计了一种大尺寸亲锌阴离子添加剂调控电解液体相环境并保护锌负极的策略。将适宜浓度的活性红2加入硫酸锌溶液中,其多极性位点能够与SO₄^2-配合协同重建Zn²⁺的溶剂化结构,强化氢键网络,降低自由水的反应活性,同时其特异性吸附作用可以在电极表面形成疏水分子保护层,诱导锌均匀剥离/沉积,并抑制负极腐蚀和正极溶解。采用复合电解质的锌对称电池在5 m A cm^-2-1 m Ah cm^-2条件下极化电压仅78.4 m V且稳定循环超过1120圈。Zn//Na V₃O₈·1.5H₂O全电池在4.0 A g^-1下提供较高的平均比容量(170m Ah g^-1)且循环超过1000圈,展现出良好的稳定性和可逆性。该工作阐明了阴离子型添加剂在负极-电解质界面中的关键作用,对电解液设计具有参考意义。（2）提出了一种痕量牺牲型两性离子添加剂重构负极-电解质界面化学以稳定锌剥离/沉积的策略。将痕量浓度的罗丹明B引入硫酸锌电解液中,其大分子体积和丰富的极性位点可以加强氢键网络,提升Zn²⁺离子迁移数,同时罗丹明B两性电荷可在负极-电解质界面重构双电层并原位构建有机-无机复合SEI,诱导锌均匀的（002）取向生长。结果表明,采用复合电解质的锌对称电池可以耐宽电流密度并在5 m A cm^-2-1 m Ah cm^-2条件下稳定运行超过2320圈（928 h）,同时Zn//Na V₃O₈·1.5H₂O全电池可以在4.0 A g^-1电流密度下提供接近200 m Ah g^-1的比容量且循环超过1200圈。该工作揭示了牺牲型添加剂原位构建SEI的演变机制,对低成本设计稳定界面具有指导意义。（3）构建了一种外磁场作用提升锌离子电池深度放电性能的体系。通过商用永久磁铁钕铁硼叠加在电池两侧施加外磁场作用,在电磁耦合效应下锌离子以螺旋式迁移,均匀界面离子浓度场,消除负极表面异质性,同时大电流密度下可促进锌以（101）侧面紧密堆积暴露均匀的（002）表面。因此,电磁耦合作用下的锌对称电池可以在10 m A cm^-2-5 m Ah cm^-2条件下表现出1500 h的长循环寿命,同时在20m A cm^-2-30 m Ah cm^-2深度放电条件下仍可稳定循环340 h。该工作工艺简单、性能改善明显,对于高能锌离子电池的开发具有重要意义。图64幅,表3个,参考文献182篇更多还原

【Abstract】 Aqueous zinc-ion batteries have great application prospects in large-scale energy storage due to their high natural abundance of zinc,low cost and high safety.However,the cycling life limited by side ractions（hydrogen evolution reaction,corrosion）and dendrite growth at anode-electrolyte interface hinder the practical development of zinc-ion batteries.In this work,the influence of internal and external factors on reaction environment at anode-electrolyte interface and the change of zinc stripping/plating behavior are studied based on electrolyte optimization strategy of additives and electromagnetic coupling effect,the schemes are proposed to stabilize zinc anode and improve the performance of batteries.The relevant mechanisms are also deeply explored.The main research works are shown as follows:（1）A strategy for regulating bulk phase electrolyte environment and protecting anode is proposed by introducing large size zincophilic anion additive into Zn SO₄ electrolyte.Owing to its multipolar sites,Procion Red MX-5b can cooperate with SO₄^2-to reconstruct solvation structure of Zn²⁺,strengthen hydrogen bond network,and reduce the reactivity of free H₂O.Meanwhile,its specific adsorption can form a protective layer of hydrophobic molucules on the electrode surface,thus inducing uniform zinc stripping/plating behavior and inhibiting corrosion of anode and micro-dissolution of active material.The Zn//Zn symmetric cell with composite electrolyte is able to cycle for over 1120 cycles at 5 m A cm^-2-1 m Ah cm^-2 with a low voltage hysteresis（only 78.4 m V）and Zn//Na V₃O₈·1.5H₂O full cell can run more than 1000 cycles with high capacity(average 170 m Ah g^-1)at 4.0 A g^-1,showing great stability and reversibility.This work elucidates the key role of anion additives in the anode-electrolyte interface and provide reference significance for electrolyte design.（2）A strategy of trace sacrificial zwitterion additive to reconstruct anode-electrolyte interface chemisrey is designed to stabilize zinc stripping/plating.Rhodamine B with large size and abundant polar sites can strengthen hydrogen bond network and increase transference number of Zn²⁺ions.Furthermore,the amphoteric charge of Rhodamine B can reconstitute interfacial electric double layer and achieve in-situ formation of organic-inorganic composite SEI,thus inducing the uniform and oriented growth of Zn（002）.The results show that Zn//Zn symmetric cell with composite electrolyte can withstand a wide current density and operate stably for more than 2320 cycles（928 h）at 5 m A cm^-2-1 m Ah cm^-2.Meanwhile,Zn//Na V₃O₈·1.5H₂O full cell exhibits a high specific capacity(nearly 200 m Ah g^-1)for over 1200 cylces at 4.0 A g^-1.This study reveals the evolution mechanism of in-situ SEI construction through sacrificial additives and has guiding significance for low-cost design strategies of stable interface.（3）A system with external magnetic field is developed to enhance performance of aqueous zinc-ion batteries at high depth-of-discharge.The electromagnetic coupling effect from commercial permanent magnent Nd Fe B superimposed on both sides of cell can induce Zn²⁺to migrate in spiral mode,homogenize interfacial ion concentration field,eliminate the heterogeneity of zinc anode surface,even promote compact packing of zinc on the（101）side and expose uniform（002）surface at high current density.Therefore,Zn//Zn symmetric cells under electromagnetic coupling show long cycling life of 1500 h at 10 m A cm^-2-5 m Ah cm^-2 and stable cycles of 340 h at deep discharge condition of 20 m A cm^-2-30 m Ah cm^-2.The strategy is simple and effective for the improvement of electrochemical performance,which is of great significance for the development of high energy aqueous zinc-ion batteries.更多还原