| Super absorbent polymer（SAP）is the main raw material for recyclable resources such as disposable diapers,and it is important to study this material for resource recycling.Moreover,based on the synchronous activation-catalytic graphitization strategy,the high-temperature pyrolysis of metal salt-superabsorbent water-absorbing resin can directly obtain porous graphitized carbon materials for supercapacitor electrode materials.In this paper,porous graphitized carbon and transition metal oxide composite porous carbon were constructed by combining metal salts with different compositions and contents with superabsorbent resins for high-performance supercapacitors.This research is expected to inspire and stimulate widespread interest in the exploration of the synthesis of superabsorbent resin-derived carbon materials and their composites,as well as applications as electrode materials for supercapacitors.The main contents are as follows:（1）Diacetate synchronous activation-catalytic graphitic strategy and potassium acetate"salt-in-water"electrolyte to prepare porous graphitic carbon and high-voltage drainage electrolyte for high-performance symmetric supercapacitors.In this project,a synchronous activation-catalytic graphitization strategy（potassium acetate+nickel acetate）was proposed for the first time to prepare SAP-derived porous graphitized carbon（PGC）as an electrode material.PGC combines the well-developed pore structure of porous carbon（PC）with the high conductivity of graphitized carbon（GC）,and also has a reasonable pore structure distribution.Compared to potassium acetate-activated PCs,PGC shows higher specific capacitance values,longer cycle life,and better rate capability.On the other hand,the potential of potassium acetate in raising the voltage window of the electrolyte is also being tapped for carbon-based supercapacitors.In this work,a water-in-salt and water-in-salt potassium acetate aqueous electrolyte was designed for symmetric carbon-based supercapacitor applications,and the LSV results showed that the water-in-salt type 22 M potassium acetate electrolyte had a significant effect in increasing the voltage window,operating up to 2.95 V.When applied to supercapacitor devices,the operating voltage window extends from 1.6 V（2 M KAc）to 2.2 V（22 M KAc）and the energy density of the device increases from 17.1 Wh kg-1to 40.6 Wh kg-1.In addition,the self-discharge performance test of the device shows that both porous graphitized carbon and water-in-salt electrolyte are conducive to improving the self-discharge performance.（2）Potassium perferrate and potassium permanganate were prepared to synthesize metal oxide composite porous carbon to construct asymmetric supercapacitors with high energy density.In this project,SAP was used as the carbon source to prepare porous graphitized carbon by activation-catalytic graphitization of potassium perferrate,metal oxide composite porous carbon was prepared by rapid low-temperature hydrothermal synthesis process,and then iron oxide composite porous carbon/manganese dioxide composite porous carbon was constructed as anode/cathode materials and assembled into asymmetric supercapacitors.In the hydrothermal process,the loading amount of iron oxide nanoparticles can be easily adjusted by changing the content of potassium perferite,and a higher specific surface area and a higher specific capacitance value can be achieved under moderate loading conditions.Iron oxide composite porous carbon and manganese oxide composite porous carbon showed specific capacitance values of up to 620 F g-1and 558.0 F g-1,respectively,with rate capacities of 62.8%and 45.3%,respectively.In the low temperature rapid hydrothermal process,the strong oxidation of potassium perferdate and potassium permanganate promotes the tight binding of metal oxides to carbon substrates,which ultimately leads to higher rate capacity.The assembled ASC device exhibits typical pseudocapacitor characteristics,with a high energy density of 33.3Wh kg-1at a power density of 400 W kg-1,much higher than conventional electric double-layer capacitors. |
PDF Full Text Request