Synthesis Of 3D Nanomaterials And Their Applications In Zinc-Based Batteries

Due to the increasingly severe living environment conditions and the huge demand for renewable energy,peopleare in pursuit of efficient,environmentally friendly and economic benefits of energy demand in various fields,such as energy storage systems and flexible wearable devices.These stimulate the prosperity and development of high-specific-energy lithium ion batteries（LIBs）.However,these factors,including the low abundance of lithium metals,the difficulty of recycling and the utilization of toxic,flammable organic electrolytes,reflect the rising costs of LIBs and the harm of environment.Therefore,aqueous zinc-based batteries,especially zinc-air batteries（ZABs）and zinc-ion batteries（ZIBs）,are considered as candidates to replace lithium-ion batteries.On the other hand,the metal zinc electrode has the advantages of easy availability,high theoretical capacity(5854 m Ah cm^-3),high REDOX potential（-0.76 V vs.SHE）,and stability in water.However,in zinc-air battery,the oxygen evolutionreaction（OER）and oxygen reduction reaction（ORR）of the air cathode reflect slow kinetics and high overpotential.Similarly,in zinc-ion battery,the dendrites of zinc negative electrode lead to serious polarization phenomenon and the damage to membrane,which decrease cycling stability of ZIBs.Therefore,pairing the economical and efficient cathode materials and the solid and uniformly deposited zinc cathode has turned into the pursuit of aqueous zinc-based batteries with high electrochemical performance.Based on the above,this paper carried out the following work in the aspects of the design,performance optimization and mechanism research of the anode and cathode materials in zinc-based batteries,and obtained the following beneficial conclusions:1.Pt nanoparticles modified Zn nanoplates（NPS）heterostructure catalyst Pt/Zn NPS was designed by two-step electrochemical deposition method.And the doping amount of Pt was adjusted and optimized by controllable means.In neutral environment,compared with commercial Pt/C,it shows comparable ORR and OER electrocatalytic performance and long cycle stability.This composite material can reduce the amount of precious metal Pt,maintain the catalytic performance of Pt itself and provide enough active sites,so it has a synergistic effect to improve the catalytic performance.When Pt/Zn NPs were applied to air electrodes for neutral zinc air batteries,it shows a high power density of 45 m W cm^-2 and excellent stability of more than 850 cycles.At the same time,it also shows a good application prospect in flexible neutral ZABs.2.Thanks to build 3D porous titanium nitride nanorods（NTs）with high conductive frame,we have realized the uniform deposition of metal zinc to prepare dendrite-free zinc cathode（Zn/TiN NTs）.Moreover,via the different deposition current,the growth of zinc crystals were successfully regulated.Thus,this controllable mean inhibits the polarization phenomenon and reduces the subsequent emergence of dendrites,which further extend the service life of zinc ion battery and improve the capacity.A series of electrochemical tests showed that TiN NTs have abundant active adsorption sites and avoide the local aggregation of Zn²⁺.The symmetric cell based on Zn/TiN NTs has excellent stability of 300 hours at a high current density of 5 m A cm^-2,while the capacity of Zn/TiN NTs//Mn O₂ full cell has a capacity of more than 250 m Ah g^-1 at 1A g^-1 and maintainthe capacity for 400 cycles.At the same time,the fibrous flexible ZIBswere also designed and displayed the outstanding electrochemical performance,which expand their application in flexible wearable devices.