| Over the past decade,integrated innovative electronics,such as wearable devices,flexible displays and implantable medical devices have experienced a rapid development and have aroused the widespread attention of researchers.Since most of the flexible electronics run on electricity,there is a persistent demand for advanced flexible power sources.However,current power sources are generally too thick,bulky,rigid,and heavy to satisfy the requirement of flexible energy storage.Therefore,micro and flexible energy storage system is the development trend of modern electronic technology.Current efforts are focused on developing superior energy devices that maintain excellent electrochemical performance,mechanical properties and safety under external pressure.Among them,lithium-ion batteries(LIBs)have been widely recognized as an ideal flexible energy storage medium because of their lighter mass and high volumetric energy density.Zinc ion batteries(ZIBs)have also attracted great attention owing to their characteristics of cost-effectiveness,environmental-friendliness and the safety.Based on the synthesis of electrode materials and current collector,development of electrode structures,this dissertation aims at fabricating high performance flexible LIBs and ZIBs and expanding its applications form in wearable electronics.It mainly includes:1.Metal germanate nanospheres including Ca2Ge7O16,Zn2GeO4 and SrGe 4O9 were successfully synthesized by a direct and large-scale electrospraying method.As anodes for lithium ion batteries,the prepared metal germanate nanospheres showed high electrochemical lithium storage performance including excellent cycling stability and high rate capacity.Especially,the Ca2Ge7O16 nanosphere anode delivered a high specific capacity of～670 mA h g-1 at 0.2 A g-1.The capacity retention was maintained around 71%even after 500 cycles.The flexible full cells were composed of tyrene-isoprene styrene rubber(SIS)/carbon nanotubes(CNTs)current collectors,Ca2Ge7O16 anode,commercial LiCoO2 cathode and electrolyte,exhibiting high flexibility and excellent electrical stability.2.We used a controlled two-step method including electrospraying followed with calcination treatment by CVD furnace to design novel electrodes of SiOx/C and Sn/C microrods array consisting of nanospheres on flexible carbon cloth substrate(SiOx/C@CC,Sn/C@CC).Microrods composed of cumulated nanospheres(the diameter was～120 nm)had a mean diameter of approximately 1.5 μm and a length of around 4.0 μm,distributing uniformly along the entire woven carbon fibers.Both of Si/SiOx/C@CC and Sn/C@CC products were synthesized as binder-free anodes for Li-ion battery with the features of high reversible capacity,high rate capacity and excellent cycling.Especially SiOx/C electrode exhibited a high specific capacity of about 1850 mAh g-1 at 0.5 A g-1 and excellent cycling ability even after 1050 cycles with a capacity of 1388 mAh g-1.Highly flexible SiOx/C@CC//LiCoO2 batteries based on liquid and solid electrolytes were also fabricated,exhibiting high flexibility,excellent electrical stability and superior electrochemical performances.3.Herein,a flexible all-solid-state in-plane Zn-polyaniline(PANI)micro-battery with concentric circle structure is reported by directly electrodepositing both positive and negative electrode materials on tyrene-isoprene styrene rubber(SIS)substrate.As-fabricated battery delivers a high specific area capacity of 250 μAh cm-2,a high energy density(0.25 mWh cm-2)and a high power density(0.99 mW cm-2)as well as excellent cyclin stability(68%capacity retention after 1200 cycles).More importantly,the concentric circle structured micro-battery exhibits superior mechanical flexibility,reasonable stretchability,outstanding waterproof ability,and temperature resistance up to 80℃ and excellent integratability with wireless charging coils... |
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