De­sign of new me­tal­lic oxide-​carbon hy­brid com­po­si­tes for su­per­ca­pa­ci­tors elec­tro­des - MOC@SUP­CAP

Pro­ject sum­ma­ry

The ob­jec­ti­ve of the MOC@SUP­CAP pro­ject is to de­ve­lop a novel class of hy­brid com­po­si­te elec­tro­des with high per­for­mance tar­ge­ted for the next ge­nera­ti­on su­per­ca­pa­ci­tors, na­me­ly asym­metric su­per­ca­pa­ci­tors, based on cheap and re­li­a­ble fa­bri­ca­ti­on me­thods. Needs ad­dres­sed: Su­per­ca­pa­ci­tors (SC) are en­er­gy sto­rage de­vices, es­sen­ti­al to sup­port the peak loads/con­sump­ti­on in re­ne­wa­bles pro­duc­tion and that can com­ple­ment bat­te­ries due to their hig­her power den­si­ty. SC ex­hi­bit un­i­que fea­tures such as high power den­si­ty, and fast char­ge/dischar­ge rates, sus­tai­ning up to mil­li­ons of cy­cles. How­e­ver, they lack en­er­gy den­si­ty when com­pa­red to bat­te­ries. This draw­back can be mi­ti­ga­ted by de­ve­lo­ping new elec­tro­de ma­te­ri­als com­bi­ning hig­her spe­ci­fic ca­pa­ci­tance and the­re­fo­re en­han­ced power and en­er­gy den­si­ties. The ans­wer re­si­des in de­ve­lo­ping new com­po­si­te elec­tro­des with high­ly po­rous hier­ar­chi­cal struc­tu­res, com­bi­ning en­han­ced dou­ble layer ca­pa­ci­tance, ty­pi­cal of carbon-​based ma­te­ri­als with the pseu­do­ca­pa­ci­tance be­ha­viour of tran­si­ti­on metal oxi­des. Com­po­si­te elec­tro­des com­po­sed of tran­si­ti­on me­tals oxi­des (NiO2, Co3O4, MnO2 and V2O5) and car­bon (like cloth/fibre and gra­phe­ne) are a pro­mi­sing route when tailo­red as po­rous hier­ar­chi­cal two-​dimensional (2D) or three-​dimensional (3D) struc­tu­res. The pre­pa­ra­ti­on of these struc­tu­res should, how­e­ver, be simp­le and fle­xi­ble, al­lo­wing fine tu­ning of the sur­face pro­per­ties in order to ful­fil the re­qui­re­ments of elec­tro­des for high per­for­mance SC. The in­no­va­ti­ve con­tri­bu­ti­on lies in the de­sign and fa­bri­ca­ti­on of de­po­si­ted tailor made tran­si­ti­on me­tal­lic oxi­des on C based sub­stra­tes to ob­tain high per­for­mance com­po­si­te elec­tro­des. The me­tal­lic oxi­des will be ob­tai­ned by simp­le, fle­xi­ble and low-​cost rou­tes (elec­tro­de­po­si­ti­on and wet che­mi­cal syn­the­sis me­thods) which are ea­si­ly scaled-​up. For examp­le, the pro­duc­tion of struc­tu­red oxi­des by pul­sed ca­tho­dic elec­tro­de­po­si­ti­on is a novel ap­proach to this pro­cess that is al­rea­dy wi­de­ly used in the in­dus­try for the pro­duc­tion of coa­tings. Re­sults: A new class of hy­brid com­po­si­te elec­tro­des based on as­sem­blies of car­bon ma­te­ri­als (for en­han­ced dou­ble layer re­spon­se) and po­rous tran­si­ti­on me­tals oxi­des (for high fa­ra­daic con­tri­bu­ti­on) will be de­ve­lo­ped. The com­bi­ned ad­van­ta­ges of car­bon with those of tran­si­ti­on me­tals oxi­des will en­able more ef­fec­ti­ve su­per­ca­pa­ci­tors, able to work with en­vi­ron­mental­ly friend­ly aque­ous elec­tro­ly­tes. Fur­ther­mo­re they can be ea­si­ly as­sem­bled in asym­metric de­vices, which com­bi­ne a bat­te­ry elec­tro­de with a su­per­ca­pa­ci­tor elec­tro­de. A spe­ci­fic ca­pa­ci­tance above 500 Fg-1, an ope­ra­ting vol­ta­ge lar­ger than 1.5 V and high cy­cling sta­bi­li­ty will be tar­ge­ted as sought-​after cha­rac­te­ris­tics of the de­si­gned hy­brid com­po­si­te elec­tro­des. The MOC@SUP­CAP pro­ject out­puts are: - more ef­fi­ci­ent com­po­si­te su­per­ca­pa­ci­tor elec­tro­des con­sis­ting of car­bon and tran­si­ti­on me­tal­lic oxi­des, with ad­di­tio­nal abi­li­ty to un­der­go va­rious redox pro­ces­ses; - the im­ple­men­ta­ti­on of che­a­per fa­bri­ca­ti­on pro­ces­ses ca­pa­ble of pro­du­cing novel clas­ses of na­nost­ruc­tu­red po­rous oxi­des/car­bon com­po­si­te ma­te­ri­als; - to fos­ter new Hi-​Tech ap­p­li­ca­ti­ons, com­bi­ning the tra­di­tio­nal elec­tro­de­po­si­ti­on or wet che­mi­cal me­thods of pro­du­cing me­tal­lic oxi­des with new ad­van­ced ma­te­ri­als such as gra­phe­ne; - ad­van­ced phy­si­cal, che­mi­cal and elec­tro­che­mi­cal cha­rac­te­ri­sa­ti­on and fun­da­men­tal know­ledge on elec­tro­che­mi­cal be­ha­viour of such elec­tro­des using tran­si­ent ma­the­ma­ti­cal mo­dels, pre­dic­ting ef­fi­ci­en­cy, per­for­mance and life­time. The pro­ject ad­dres­ses some of the most im­portant con­cerns of cur­rent times: sus­tain­able en­er­gy pro­duc­tion and ef­fi­ci­ent en­er­gy sto­rage for a clea­ner en­vi­ron­ment while con­tri­bu­ting to sus­tain­able eco­no­mic growth, boos­ting of new mar­kets, crea­ti­on of jobs and so­cial well being. The pro­po­sal is thus, by no doubt, in the scope of the call topic "Ma­te­ri­als for En­er­gy Sys­tems".