Research On 3D Printing Of Functionalized Battery And Their Electrochemical Performance

In recent years,the rise of multifunctional wearable electronics has stimulated a high demand for flexible and reliable energy storage devices.Three fundamental elements of electrode fabrication,modification,and assembly largely determine the electrochemical behavior of energy storage devices.Meanwhile,3D printing technology is considered as a revolutionary and attractive process for the fabrication of electrochemical energy storage devices.Compared with traditional manufacturing methods,3D printing has unique advantages in geometry design and rapid prototyping,especially for complex 3D structures with high surface area.The well-designed 3D-printed electrodes offer excellent electrode thickness controllability,thereby tuning the active material loading.This technique enables the fabrication of high-aspect-ratio structures in a small area,thereby facilitating rapid diffusion of ions/electrons through thick electrodes.This not only shows better performance in electrochemical energy storage,but also meets the market’s high requirements for customization,flexibility and design complexity.However,many challenges remain in the formulation of printable electrode inks,high-performance electrode materials,and device design.This work is based on 3D printing technology and aims to develop 3D printing wearable high-performance energy storage devices.Starting from the development of 3D printing equipment,combined with the functional modification of materials.A series of 3D printed electrodes were prepared with graphene,copper powder,and manganese dioxide electrode materials,and the preparation of 3D printed wearable batteries was realized.The specific work mainly includes the following five parts.（1）Design and assembly of 3D printed battery manufacturing equipmentUsing a low-cost and high-precision 3D printer open-source solution,with linear guides as the motion platform and stepper motors as the driving method,Core XY has developed 3D printing equipment for the motion mechanism.The components and structure of the 3D printing equipment are designed to be modular and have strong flexibility.At the same time,the equipment has rich expandability and can be quickly expanded into laser engraving and desktop CNC equipment.This equipment provides a basis for the subsequent processing and manufacturing of battery electrodes,and also provides new ideas for the development of other non-standard experimental equipment in the laboratory.（2）Research on 3D printing high sulfur-loading Li-S battery and its electrochemical performanceA 3D lithium-sulfur battery wristband based on direct ink writing and fused deposition was designed and fabricated using 3D printing.A graphene/phenol formaldehyde（PF）resin slurry with excellent viscoelasticity was used as a writing ink for 3D printing,in which the addition of phenolic resin enabled the printed cathode skeleton to have good mechanical strength after curing.Meanwhile,a porous cathode framework for sulfur storage was prepared by a classical Si O₂ template method.The 3D printed cathode produced by the 3D printing method has an ultra-high active material loading of about 10.2 mg cm^-2（the amount of electrolyte is 202μL）,an initial capacity of 967.9 m Ah g^-1,the sulfur utilization rate is 57.8%,and 505.4 m Ah g^-1 capacity after 500 cycles at a current density of 0.2C.In addition,the 3D printed battery case is fabricated by fused deposition 3D printing technology.A 3D Li-S bracelet battery was designed and fabricated by combining two 3D printing methods.The battery successfully lights up the LED lamp beads,verifying that it is working properly.This indicates that advanced 3D printing technology is environmentally friendly,low-cost,and scalable,and can provide a promising solution for wearable electronic devices.At the same time,a series of molecular dynamics（MD）models representing carbonate electrolyte systems for lithium-sulfur batteries were constructed using computer simulations.The detailed composition of the first solvation shell of lithium ions and Li₂S₄,the coordination number of the ions,and the diffusion coefficient of the electrolyte are calculated and discussed.Therefore,molecular dynamics simulations of carbonate-based electrolytes will effectively predict future properties of solvation structures and transport processes in complex electrolytes to optimize current lithium-sulfur battery systems.（3）Research on 3D printing of full batteries based on high-performance lithium metal anodes and their electrochemical performanceA high-performance 3D current collector for lithium metal batteries was prepared by 3D printing a copper powder paste with appropriate viscosity to form a grid structure.The 3D copper mesh has a high-aspect-ratio structure in a small volume,providing more electroactive sites and keeping the deposited lithium metal inside,while making the electric field distribution more uniform and effectively controlling the current density.Combined with computer simulations,experimental studies were carried out to confirm that 3D printed frameworks can induce dendrite growth inside electrodes at low current densities.The open structure of the 3D copper mesh can effectively reduce the occurrence of dead lithium and improve the Coulombic efficiency and battery cycle life.The results show that the 3D copper mesh has significant advantages in improving the rate capability and cycle life of Li metal anodes,enabling safe charge-discharge at ultra-high current densities of 50 m A cm^-2,which exceeds most reported studies.In addition,a representative 3D fully-printed lithium-sulfur battery was assembled with3D-printed high-load sulfur cathode,which can easily light up 51 LED indicators.It is indicated that the 3D printed copper mesh anode current collector has the characteristics of high energy density and high safety,and has wide application potential.（4）Research on 3D printed quasi-solid-state gel-based zinc-ion battery and its electrochemical performanceA 3D flexible quasi-solid-state zinc-ion battery based on direct ink writing was designed and fabricated using 3D printing.Conductive silver paste with excellent electrical conductivity was printed on PET base film as a conductive current collector for flexible batteries.Meanwhile,carbon-coated Mn O₂ nanowires were prepared by hydrothermal method as cathode material.Commercial zinc powder was used as the negative electrode.The positive and negative electrode materials were formulated into a slurry with excellent viscoelasticity,printed on the current collector by 3D printing method,and then dried and then printed with the PVA gel electrolyte on a PET substrate to obtain a 3D fully printed flexible quasi-solid-state zinc-ion battery.The prepared 3D printed zinc-ion battery has an initial capacity of 267.3 m Ah g^-1 and still maintains a capacity of 189.7 m Ah g^-1 after 500 cycles at a current density of 0.2 A g^-1.Furthermore,the 3D-printed printed flexible quasi-solid-state zinc-ion battery can power a portable human heart rate sensor,suggesting that advanced 3D printing technology is environmentally friendly,low-cost,and scalable,and can provide a promising solution for wearable electronics.（5）Research on 3D printed special-shaped batteries and their electrochemical performanceA special-shaped battery is prepared by 3D printing to modify electrode slurry,which adopts functional structure design.Based on the characteristic electrodes of multi-layer biscuit structure using commercial graphite（Gt）and silicon monoxide（Si O）as raw materials,a3D special-shaped battery was fabricated through functional and structural design.The surface load of 3D Gt S is 19.1 mg cm^-2.The assembled full battery（3D Gt S//LNMO）provides a high reversible capacity of 5.3 m Ah cm^-2 at 1.8 m A cm^-2（the amount of electrolyte is 380μL）.The assembled special-shaped battery can be used as the external power supply of the aircraft to prolong the airborne time of the aircraft.The rationally designed functional structure can not only maximize the internal space of the battery,but also make the battery casing have a safe and stable structure.These works show that the structural battery combining structural carrying and 3D printing technology is versatile enough to meet the needs of structural energy storage in special application scenarios.