| Due to the constant development of integrated and wearable microelectronic technology,the demand for miniaturized and customized energy storage devices is an increasing upward.The new generation of micro energy storage devices not only need to have more excellent energy storage performance and cyclic stability,but also need to be highly compatible with micro-electro-mechanical system in characteristics of functionalization,integration and financial flexibility,such as micro-nano devices and portable electronic devices,etc.Among many micro-energy storage devices,planar micro-supercapacitors（MSCs）have attracted wide attention attributed to their high-power density,fast charge-discharge performance and excellent cycling stability.Planar interleaved interfingered MSCs can shorten ion diffusion distance and reduce transmission resistance,thus improving the rate performance and power density within limits of as-prepared devices.Simultaneously,the planar MSCs can provide new opportunities for electronic chips and wearable devices because of their lightweight,flexibility,foldability and ease of manufacturing.As a typical two-dimensional material,graphene and its derivatives deliver large surface area,excellent electrical conductivity and flexibility,thereby being one of the ideal candidate materials for flexible micro-energy storage devices.Particularly in the planar electrodes,electrolyte ions can utilize graphene’s intrinsic two-dimensional nano planes for rapidly diffusing within base nanochannels,therefore,the graphene-based MSCs show a great potential in microelectronic device.However,limited by the difficulty in mass preparation of highly electrochemically active nanomaterials and the complex preparation process of microelectrodes,high-throughput manufacturing of the advanced plane graphene MSCs with high energy density,integrability and flexibility still remains an important challenge in this domain.Focusing on the above-mentioned problem,this thesis focuses on the formulation and optimization of the composition of graphene nano-composite ink and printed electrode structure,and develops a variety of integrated and functionalized MSCs with adjustable multi-performance.Detailed research contents are listed as follows:1.Based on physical turbulent spiral delamination and screen-printing technology,we develop graphene conductive inks and microdevice,which are highly compatible with printing manufacture,and realize the construction of planar micro-supercapacitors integrated collector and active electrodes.The printable graphene conductive ink with excellent rheological properties is obtained by the unique mass transfer and shear field through interfacial friction and the dispersity of carboxyethyl methyl cellulose（CEME）.The printed Gr/CEMC electrodes are annealed at low temperature,and part of the CEMC is carbonized,leading to the increased carrier density of graphene electrodes,and significantly expanding the conductive path of the printed electrodes.The encapsulated plane Gr-MSCs deliver a good areal capacitance(1.36 m F·cm-2)and long cycle life（after 10 000 cycles,the capacity retention rate is above than 92.3%）.2.In order to address the crucial problem of low electrochemical performance of graphene MSCs caused by dense packing of graphene and insufficient active sites in printed microelectrodes,porous activated carbon is employed as the second active material to construct the electrode configuration with Gr/AC"mosaic structure".During the physical turbulent spiral delamination,the activated carbon intersperses and attaches to the graphene nanosheets,effectively blocking the restacking of graphene,simultaneously fully exerting itself rich in active sites.The electrochemical tests manifest that the MSCs with Gr/AC two-dimensional"mosaic structure"reveal a higher areal capacitance(up to 12.5 m F·cm-2),which is an order of magnitude higher than the`pure graphene MSCs.The thickness of the electrode is increased by multiple printing,and the areal capacitance of MSCs increases linearly with incremental printing times（printing passes<8）.In addition,the as-prepared Gr/AC-MSCs showcase better mechanical flexibility and series-parallel integration.Spraying technology is adopted to endow Gr/AC-MSCs devices with excellent waterproof performance,indicating that the multifunctional integrated micro-supercapacitors prepared by this strategy exhibit promising prospects in harsh environments.3.Based on the well-designed Gr/Mn O2 point-plane configuration,the hybrid graphene micro-supercapacitors with high voltage output window energy density have been developed.By introducing the pseudocapacitor material Mn O2 into the graphene lamellar,then optimizing the mass ratio of Gr and Mn O2,the synergistic relationship between conductivity and pseudocapacitance activity of printed electrodes is balanced.Individual device with optimized electrode structure exhibits high voltage output window（1.2 V）,high areal capacitance(16.1 m F·cm-2)and energy density(3.22μWh·cm-2),and the capacity retention of Gr/Mn O2MSCs is 79%after 5000 cycles.Simultaneously,after subjected to standing treatment with two months for the nano-composite ink,the reprinted Gr/Mn O2-MSCs deliver areal capacitance of 8.8 m F·cm-2,realizing the possibility of printing MSCs ink storage for a long time.4.To overcome the problems of poor active sites of graphene and unreasonable match of microelectrodes materials,the ternary complex microelectrodes with an innovative multicomponent interlaced architecture of 2D functional graphene and 1D carbon nanotubes（CNTs）have been built.By the non-covalent bonding of 2-amino-8-aphthol 6-sulfonic acid（ANS）with graphene and the excellent pseudocapacitor performance of ANS,the micro-supercapacitors with Gr@ANS layered electrode structure are achieved,and the optimized Gr@ANS（4:3）-MSCs deliver an high areal capacitance of 33.7 m F·cm-2.Afterwards,the multi-walled carbon nanotubes are elected to serve as current conduction intervals to expand the lamellar space of Gr@ANS nanosheets,and promote the migration of free electrons and the shuttling of electrolytes.The well-prepared Gr@ANS/CNTs-MSCs provide the highest areal capacitance of 40.2 m F·cm-2,energy density of 3.57μWh·cm-2,and exhibit excellent rate capability and flexibility under different strains. |
