| Owing to these advantages of low cost,simple assembly process,high safety and environmental friendliness,zinc ion batteries show great application potential among consumer electronic equipments,flexible devices and static energy storage.However,the zinc metal anodes usually face a series of challenges during long-term cycling,including hydrogen evolution,corrosion/passivation and dendritic growth,which limit the further development and industrial application of zinc ion batteries.Here,based on the zinc-ion transport pathways on the anode side,this thesis from the design perspectives of aqueous electrolytes,zinc anode structure and interfacial protective layer,developed a series of interfacial regulation strategies for zinc metal anodes,on this basis,a non-aqueous non-flammable solid eutectic electrolyte was designed to further optimize the interfacial deposition behaviour of zinc metal anodes,and carried out in-depth research on related mechanisms.Finally,its roles in promoting the stable cycle of full battery was evaluated.A novel self-healing hydrogel electrolyte（SHE）with a rigid and flexible framework was synthesized by cross-linking polymerization of agarose molecular chain and polyacrylamide,and composite strengthening with carboxymethyl cellulose.Owing to porous cross-linking network and abundant hydrophilic groups,the SHE had a high ionic conductivity(23.1 m S cm-1 at 25 oC).In addition,the dynamic hydrogen bond formed by the hydroxyl and amide group on the polymer skeleton can promote the excellent stretchable property（maximum stretch rate:1300%）and self-healing properties（stretch rate after healing:1000%）of the electrolyte.This rigid gel network structure and self-healing interface were conductive to the improved interfacial compatibility between electrode and electrolyte,and uniform zinc metal deposition behavior,resulting in stable cycling of the symmetric batteries for 300 h at 5.0 m A cm-2 and 1.0 m Ah cm-2.As a result,the assembled Zn||Mn O2 full batteries delivered a high capacity of 304 m Ah g-1 at 0.5 A g-1 and extraordinary stability with a capacity retention of 83.1%after 1500charge/discharge cycles at 5.0 A g-1.To achieve reversible zinc deposition at large current density and areal capacity,a3D porous silver nanowire aerogel（Ag NWA）with oriented structure was constructed by vertical self-assembly method.According to the first-principle calculations and phase-field simulation,Ag NWA offered appropriate Zn deposition sites and uniform electric field for Zn metal deposition,and effectively restrained the irreversible volume expansion originated from Zn metal deposition/stripping.Thus,the Ag NWA displayed ultrahigh Zn deposition/stripping efficiency of 99.8%for 200 cycles at condition of 40 m A cm-2 and10 m Ah cm-2.For practical use,the Ag NWA@Zn||α-Mn O2 full battery with 67%zinc utilization was able to operate stably for 1500 cycles at 5.0 A g-1.Even in the absence of pre-deposited zinc in the anode,the full battery still maintained a high capacity retention of 73%at 0.5 A g-1 after 600 cycles.To improve the cycling stability of thinner zinc metal anodes under high zinc utilisation,a novel ion sieve interfacial protection layer（Zn Sn F@Zn）was in situ constructed on the surface of ultrathin Zn metal anode（20μm）by chemical replacement method.Combined with theoretical calculation and experimental analysis,the ion sieve interface layer facilitated zinc ion transport and desolvation at the interface,as well as reducing the zinc deposition overpotential and inhibiting side reactions.Under 50%zinc utilization,Zn Sn F@Zn||Zn Sn F@Zn symmetrical battery can still maintain a stable cycle of 250 h at high current density of 30 m A cm-2.Matched with the high-load self-supported vanadium-based cathodes(18～20 mg cm-2)by electrospinning,the energy density retention of coin batteries（50%zinc utilization）based on cathode mass can still reach94.3%after 1000 cycles at 20.0 m A cm-2.Though assembly of pouch batteries,the whole energy density can deliver 61.3 Wh kg-1,after 300 cycles,the energy density can retain76.7%,and the capacity retention still reach 85.3%（0.53Ah）.In order to solve the inherent problems of narrow voltage window and water-induced side reactions in aqueous electrolytes,a nonflammable and nonaqueous solid-state eutectic electrolyte（PSNE）was prepared by cross-linking polymerization of eutectic electrolyte（butanedinitrile/N-methylacetamide/zinc bis（trifluoromethylsulfonyl）imide）with ethoxylated trimethylpropane triacrylate.Thanks to the anchoring effect of polymer skeleton on the solvent molecules,PSNE can possess a ionic conductivity of up to 3.94×10-3 S cm-1 at room temperature,a high Zn2+ion transport number of 0.60,and high oxidant potential(2.85 V vs Zn2+/Zn).Based on the basis of ion sieve interfacial layer modification in the previous chapter,the PSNE can further prompt that the symmetric batteries with 80%Zn utilization operated stably at current densities of 1.0 m A cm-2 and8.0 m A cm-2 for 2000 h and 1700 h,respectively.Finally,matched with K1.6Mn1.2Fe（CN）6and Na3V2（PO4）2O2F cathodes,the assembled solid state zinc-based batteries delivered high average discharge-voltage of 1.6 V and 1.9 V,respectively,and presented excellent rate performance and cycle stability at room temperature. |
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