3D Printing Connected Multi-channel Micro-lattices For Zinc Storage Properties

At present,the growing need of energy puts forward higher requirements for energy storage systems（ESM）.As a mature battery system,lithium-ion batteries（LIBs）get wide range of applications in people’s lives.LIBs expose serious flammability problems in terms of safety because of the organic electrolyte used in commercial LIBs and the presence of active lithium metal.Nowadays,frequent spontaneous combustion incidents of electric vehicles arouse widespread attention to new energy storage systems.Providing a stable energy supply needs to be an important direction for research on energy storage systems under the premise of safety.In addition,the cost of using lithium-ion batteries in large-scale energy storage is too high.Rechargeable aqueous Zn ion batteries（ZIBs）are considered as a preferable possibility for next-generation ESM because of their merits of environmental benignity,low cost,and high safety.High reliability and low cost make it suitable for large-scale energy storage.Nevertheless,the unsatisfactory cycling stability stemming from the dendrite growth and undesired side reactions of Zn anode prevent their widespread commercial adoption.Structure design can increase the area of the anode,improve the electron and ion transport,reduce the nucleation overpotential,to get the uniform deposition of Zn and promote the formation of dendrite.3D printing technology can help to alleviate it and provide new direction for solving it.Here,a novel 3D Zn metal anode with multi-channel lattice structures employing the combined 3D printing and electroless plating/electroplating techniques is reported.A series of electrochemical tests and other characterization methods prove that the electrode has unique advantages for ZIBs anode.（1）First,the polymer sample with a lattice structure is obtained by 3D printing,and the sample is metallized by electroless deposition,and then a 3D multi-channel lattices zinc metal anode（3D Ni-Zn）is obtained via electrodeposition of Ni and Zn.A series of electrochemical performance are carried out by testing symmetric cells and half cells with3D electrode.The batteries with 3D electrodes have lower nucleation overpotential（36m V）,lower electrode polarization,more stable cycle performance and Coulomb efficiency.The 3D Ni-Zn symmetric cell keeps the overpotential（41 m V）for 300 hours at 2 m A cm^-2with the capacity density of 5 m Ah cm^-2.The constructed 3D Ni-Zn anode with multi-channel lattice structure and super-hydrophilic surface can effectively ameliorate the electric-field distribution and induce the uniform deposition of Zn without Zn dendrites growth,as confirmed by simulation on current density distribution of the electrode in electrolyte and in-situ microscopic observation of Zn plating/stripping.As expected,the3D Ni-Zn cell shows highly reversible Zn plating/stripping with satisfactory Coulombic efficiency due to the low Zn nucleation overpotential and homogeneous distribution of localized electric field.（2）MnO₂,Zn Mn₂O₄ and polyaniline-intercalated vanadium pentoxide（PVO）are prepared as cathodes,which can be matched with 3D Ni-Zn electrodes to obtain rechargeable aqueous ZIBs.Among them,the full battery composed of 3D Ni-Zn anode and PVO cathode exhibits a remarkable rate capability with 52%capacitance retention even with 100-times current density expansion（only 12%for the PVO//2D Ni-Zn battery）and long-term cycling stability.The simple and cost-effective fabrication of conductive metal lattices with tunable 3D multi-channel architecture opens up new opportunities to develop other high-performance metal（such as Li,Na,K,Mg,Al） batteries.