| Zinc-ion batteries show huge application potential for large-scale power grid energy storage systems and wearable devices due to their low cost,high safety and environmental friendliness.The practical applications demand for long endurance of battery makes the development of high areal capacity zinc-ion batteries the key to the industry.However,simply increasing the mass-loading of material will directly trigger delayed electron/ion dynamic of the battery electrode.On the other hand,the design of high mass-loading structure will aggravate the instability of the electrode electrochemical structure,zinc dendrite growth and other problems,resulting in low areal capacity and fast capacity decay.Based on the above research background,this thesis designed and constructed a series of three-dimensional porous network structure electrodes based on 3D printing technology.Carbon modification and ion pre-inserting were adopted to optimize the interior structure of 3D printing electrodes.On this basis,a series of zinc ion battery electrodes and devices were constructed,and electrochemical performance and energy storage mechanism of 3D printing zinc ion batteries were systematically studied.A variety of electrochemical mechanism characterization methods were used to reveal the relationship between the areal capacity and the electrode structure of the battery,and the construction of 3D printed high areal capacity zinc ion batteries was realized.The main research contents were as follows:（1）High areal capacity zinc ion battery electrodes with three-dimensional hierarchical porous structure were designed and fabricated through effective combination of iron vanadate and reduced holey graphene oxide.3D electron/ion conducting network channel with high mass-loading was obtained.When the mass-loading of electrode was12.4 mg cm-2,the discharge capacity of the positive electrode was 344.8 m Ah g-1(at 0.1A g-1).The discharge capacity was 126.4 m Ah g-1 after 675 cycles at 2 A g-1,and the capacity retention rate was 93.3%.By further adjusting the printing parameters,a high mass loading of 24.4 mg cm-2 and a high areal capacity of 7.0 m Ah cm-2 could be obtained.At the same time,through in-depth analysis of electron transport and ion diffusion in 3D-printed electrodes,the internal relationship such as high areal capacity and high structural stability between electrode structure and electrochemical properties of 3D-printed zinc ion batteries was revealed.（2）3D printing of high areal capacity calcium vanadate-based interdigital zinc ion battery with three-dimensional carbon modified was developed to further promote the practical process of microdevices.Carbon nanotubes and reduced graphene oxide were used to realize the three-dimensional porous construction of positive and negative electrodes.Copper/zinc solid solution was designed to inhibit the growth of zinc dendrites and optimize the electrochemical stability of electrodes.The results showed that the solid-state symmetric battery could cycle stably for 1200 h at 1 m A cm-2 with a capacity of 1m Ah cm-2,and showed low polarization voltage（64.5 m V）and good rate performance.3D-printed calcium vanadate-based interdigital zinc ion battery showed a high areal capacity of 8.9 m Ah cm-2(at 0.3 m A cm-2)and areal capacity of 2.0 m Ah cm-2 after 400cycles at 5 m A cm-2.By adjusting the printing parameters,the ultra-high areal capacity of 14.9 m Ah cm-2 could be obtained.At the same time,the ion transport behavior of 3D printed zinc ion batteries was studied by in situ testing,and the zinc storage mechanism of high loading electrodes was revealed.In addition,the integration and wearable application of high-performance miniaturized zinc ion devices had been realized through 3D printing technology.（3）The three-dimensional host structure of nitrogen-doped hollow carbon nanotubes was constructed to optimize the dissolution and deposition process of zinc ions during the charging and discharging process.And 3D printed high-areal capacity nickel vanadate-based zinc ion batteries were constructed.The results showed that the solid-state symmetric battery can cycle stably for 420 h at 1 m A cm-2 with a capacity of 1 m Ah cm-2,and showed excellent rate performance.The 3D-printed nickel vanadate-based zinc ion batteries showed high areal capacity and long cycle life(areal capacity was 0.9 m Ah cm-2 after 200 cycles at the current density of 2 m A cm-2,and capacity retention rate was90.2%).Theoretical calculations and experiments confirmed that nitrogen-doped hollow carbon nanotubes significantly improved the electrochemical performance of symmetric and full cells compared with commercial carbon nanotubes.Because nitrogen doping strategy improved the zincophile characteristic of electrodes,induced uniform deposition of zinc and inhibited the formation and growth of zinc dendrites,and the hollow structure provided electron and ion transport channels improving electron and ion transport.（4）The co-pre-inserting strategy of nickel ion and calcium ion was proposed to further stabilize the internal electrochemical structure of vanadate-based electrode which reduced the energy barrier of zinc ion transport and achieved the goals of high areal capacity,high areal energy and long cycle life of 3D printed zinc ion batteries.Ni0.4Ca0.08V2O5·0.83H2O nanoribbons were prepared with dual metallic ions to extend the lattice spacing and facilitate the rapid migration of zinc ion.3D printed Ni0.4Ca0.08V2O5·0.83H2O-based zinc ion microbatteries showed high areal capacity(17.4m Ah cm-2 at 0.5 m A cm-2)and long cycle stability(0.4 m Ah cm-2 after 500 cycles at 5m A cm-2 and the capacity retention rate was 97.0%).Theoretical calculations showed a lower energy barrier of zinc ion in Ni0.4Ca0.08V2O5·0.83H2O,which promoted the rapid and stable migration of zinc ion. |
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