Supercapacitors khaws cov nqi ntawm electrode -electrolyte interface, yog li lawv qhov kev ua tau zoo yog tswj hwm los ntawm qhov chaw nkag tau yooj yim, pore qauv thiab hluav taws xob conductivity. Graphite yog txaus nyiam vim nws yog conductive, tshuaj ruaj khov thiab pheej yig, tab sis ntuj graphite flakes muaj qhov txwv tshwj xeeb ntawm thaj tsam ntawm kwv yees li 10-30 m2 / g thiab lawv cov dav hlau basal yog electrochemically es inert. Kev txhim kho tsis ntev los no ua haujlwm ntawm graphite electrodes rau supercapacitors nyob raws nraim cov kev txwv.
Graphene thiab Expanded Graphite
Exfoliating graphite rau hauv graphene los yog ob peb - cov ntawv txheej nce qhov chaw nkag tau los ntawm kev txiav txim ntawm qhov loj thaum khaws cia cov khoom siv hauv nruab nrab. Qhov kev ua tau nyuaj yog rov ua dua: cov nplooj ntawv uas rov ua dua -tag nrho poob qhov chaw tau txais thiab thaiv kev thauj khoom ion. Txoj kev uas tab tom tsim kho kom cov nplooj ntawv sib cais los ntawm spacers, lossis loj hlob ncaj qha rau ntawm cov khoom siv hluav taws xob kom cov electrode tseem nyob hauv txoj kev txuas mus ntxiv. Expanded graphite, uas yog tsim los ntawm intercalating thiab thermally shocking ntuj flake, muaj ib tug nruab nrab hauv av nrog tus nqi qis rau ib cheeb tsam.
Heteroatom Doping
Qhia txog nitrogen los yog boron rau hauv cov pa roj carbon lattice hloov cov qauv hluav taws xob thiab ntxiv qhov ua haujlwm saum npoo. Nitrogen doping, tshwj xeeb tshaj yog, ua kom cov electron ceev nyob ze ntawm Fermi theem thiab txhim kho wettability ntawm cov electrolytes, uas nce lub peev xwm siv tau thiab txo qhov sib npaug sib npaug. Doping yog ib txwm ua thaum lub sij hawm sib txuas los yog tom qab- kev kho mob nyob rau hauv ib qho chaw reactive, thiab cov txiaj ntsig yog nyob ntawm seb qhov dopant sib raug zoo li cas es tsis yog ntawm nws cov concentration tag nrho.
Kev xeem thiab kev ua yam ntxwv
Electrochemical kev ua tau zoo yog soj ntsuam los ntawm cyclic voltammetry, galvanostatic nqi- paug thiab electrochemical impedance spectroscopy, siv peb lub xov tooj ntawm tes electrode rau kev soj ntsuam cov khoom thiab ob-electrode symmetric cell rau cov cuab yeej- cov txiaj ntsig cuam tshuam. Cov yam ntxwv ntawm tus yam ntxwv yog nyob ntawm nitrogen adsorption rau thaj chaw saum npoo thiab pore faib, X-ray diffraction rau interlayer spacing, thiab Raman spectroscopy rau qhov tsis xws luag. Rau cov khoom siv graphite feem ntau, kev ntsuas qhov ntom thiab qhov porosity ua raws li txoj hauv kev xws li ASTM C559 thiab ASTM C1039, thiab hluav taws xob tiv thaiv ntawm cov khoom siv carbon thiab graphite yog ntsuas los ntawm ASTM C611.
Cov lus nug nquag
Q:Vim li cas graphite siv hauv supercapacitor electrodes?
A: Nws yog cov khoom siv hluav taws xob, electrochemically ruaj khov hla lub qhov rais dav dav thiab tus nqi qis, thiab nws tuaj yeem ua tiav rau hauv cov ntawv, foils lossis coated electrodes yam tsis muaj polymer binders hauv qee qhov qauv tsim.
Q:Dab tsi txwv qhov capacitance ntawm graphite dawb?
A: Nws qhov chaw nkag tau qis qis ntawm kwv yees li 10-30 m2 / g thiab qhov sib nrug nqaim, uas txwv kev nkag mus rau ion thiab tiv thaiv kev tsim ob txheej txheej.
Q:Nitrogen doping pab li cas?
A: Nws hloov kho cov qauv hluav taws xob thiab qhov chaw chemistry, txhim kho electrolyte wetting thiab them nqi hloov pauv, uas ua rau muaj peev xwm siv tau thiab txo qis qhov sib npaug sib npaug.
Q:Dab tsi yog qhov teeb meem tseem ceeb ntawm graphene electrodes?
A: Restacking. Cov nplooj ntawv rov- sib sau ua ke thaum ziab thiab caij tsheb kauj vab, poob ntawm thaj chaw uas ua rau graphene txaus nyiam thiab thaiv kev thauj ion ntawm cov txheej.
Q:Qhov kev ntsuas twg qhia seb qhov chaw puas nkag tau tiag tiag?
A: Nitrogen adsorption muab qhov pore loj faib, thaum impedance spectroscopy thiab ntsuas ntsuas qhia qhov twg ntawm thaj chaw ntawd ua haujlwm ntawm qhov kev npaj ua haujlwm tam sim no.