Onjiniyela benze isihlukanisi esizinzisa ama-electrolyte egesi ukwenza amabhethri okushisa aphansi kakhulu aphephe kakhudlwana

Ngokwemibiko yabezindaba yangaphandle, onjiniyela be-nano eNyuvesi yaseCalifornia eSan Diego benze isihlukanisi sebhethri esingasebenza njengesithiyo phakathi kwe-cathode ne-anode ukuvimbela i-electrolyte yegesi ebhethrini ukuthi ingahwamuli. I-diaphragm entsha ivimbela ukucindezela kwangaphakathi kwesiphepho ekuqoqeni, ngaleyo ndlela kuvimbele ibhethri ekuvuvukeni nasekuqhumeni.

Umholi wocwaningo, uZheng Chen, uprofesa we-nanoengineering e-Jacobs School of Engineering eNyuvesi yaseCalifornia, eSan Diego, uthe: "Ngokubamba ama-molecule egesi, ulwelwesi lungakwazi ukusebenza njenge-stabilizer yama-electrolyte aguquguqukayo."

Isihlukanisi esisha singathuthukisa ukusebenza kwebhethri kumazinga okushisa aphansi kakhulu. Iseli yebhethri esebenzisa i-diaphragm ingasebenza kokungu-40°C, futhi umthamo ungaba phezulu njengamahora angu-500 milliampere ngegremu, kuyilapho ibhethri ye-diaphragm ethengisayo inamandla acishe abe nguziro kulesi simo. Abacwaningi bathi noma ishiywe izinyanga ezimbili ingasetshenziswa, umthamo webhethri usephezulu. Lokhu kusebenza kubonisa ukuthi i-diaphragm nayo inganweba impilo yokugcina. Lokhu kutholakala kuvumela abacwaningi ukuba bafeze umgomo wabo ngokuqhubekayo: ukukhiqiza amabhethri angahlinzeka ngogesi ezimotweni ezisendaweni eneqhwa, njengemikhumbi-mkhathi, amasathelayithi, nemikhumbi yasolwandle.

Lolu cwaningo lusekelwe ocwaningweni olwenziwe elabhorethri ka-Ying Shirley Meng, uprofesa we-nanoengineering eNyuvesi yaseCalifornia, eSan Diego. Lolu cwaningo lusebenzisa i-electrolyte yegesi ewuketshezi ethile ukuze kwakhiwe ibhethri elingagcina ukusebenza kahle endaweni kususwe u-60°C okokuqala ngqa. Phakathi kwazo, i-electrolyte yegesi eyi-liquefied iyigesi efakwa uketshezi ngokufaka ingcindezi futhi imelana kakhulu namazinga okushisa aphansi kunama-electrolyte oketshezi endabuko.

Kodwa lolu hlobo lwe-electrolyte lunesici; kulula ukushintsha kusuka oketshezini kuya kwegesi. U-Chen uthe: "Le nkinga iyinkinga enkulu yokuphepha yale electrolyte." Ingcindezi idinga ukunyuswa ukuze kufinyezwe ama-athomu awuketshezi futhi kugcinwe i-electrolyte isesimweni esiwuketshezi ukuze isebenzise i-electrolyte.

Ilabhorethri kaChen yasebenzisana noMeng no-Tod Pascal, uprofesa we-nanoengineering eNyuvesi yaseCalifornia, eSan Diego, ukuxazulula le nkinga. Ngokuhlanganisa ubuchwepheshe bochwepheshe bekhompiyutha abafana noPascal nabacwaningi abafana noChen noMeng, kuye kwasungulwa indlela yokucwilisa i-electrolyte ehwamukayo ngaphandle kokufaka ukucindezela okukhulu ngokushesha. Abasebenzi okukhulunywe ngabo ngenhla baxhumene ne-Materials Research Science and Engineering Centre (MRSEC) yaseNyuvesi yaseCalifornia, eSan Diego.

Le ndlela iboleka esenzakalweni esibonakalayo lapho amangqamuzana egesi ajiya ngokuzenzakalelayo lapho evaleleke ezikhaleni ze-nano-scale. Lesi simo sibizwa ngokuthi i-capillary condensation, engenza igesi ibe uketshezi ngomfutho ophansi. Ithimba labacwaningi lisebenzise lesi senzakalo ukuze lakhe isihlukanisi sebhethri esingazinzisa i-electrolyte kumabhethri okushisa aphansi kakhulu, i-electrolyte yegesi ewuketshezi eyenziwe ngegesi ye-fluoromethane. Abacwaningi basebenzise i-porous crystalline material ebizwa ngokuthi i-metal-organic framework (MOF) ukuze bakhe ulwelwesi. Into eyingqayizivele nge-MOF ukuthi igcwele izimbotshana ezincane, ezingabamba ama-molecule egesi e-fluoromethane futhi iwafinye ngomfutho ophansi uma kuqhathaniswa. Isibonelo, i-fluoromethane ivamise ukushwabana ku-30°C futhi ibe namandla angu-118 psi; kodwa uma i-MOF isetshenziswa, ukucindezela kwe-condensation ye-porous ekushiseni okufanayo kungu-11 psi kuphela.

U-Chen uthe: "Le MOF inciphisa kakhulu ingcindezi edingekayo ukuze i-electrolyte isebenze. Ngakho-ke, ibhethri yethu inganikeza inani elikhulu lomthamo emazingeni okushisa aphansi ngaphandle kokuwohloka." Abacwaningi bahlole isihlukanisi esisekelwe ku-MOF kubhethri ye-lithium-ion. . Ibhethri ye-lithium-ion iqukethe i-fluorocarbon cathode kanye ne-lithium metal anode. Ingakwazi ukuyigcwalisa ngegesi ye-fluoromethane electrolyte ngengcindezi yangaphakathi engu-70 psi, ephansi kakhulu kunokucindezela okudingekayo ukuze kufakwe uketshezi lwe-fluoromethane. Ibhethri lisengakwazi ukugcina izinga lokushisa elingu-57% legumbi lalo lingaphansi kuka-40°C. Ngokuphambene, ezingeni lokushisa elifanayo nokucindezela, amandla ebhethri ye-diaphragm yezohwebo esebenzisa i-electrolyte yegesi equkethe i-fluoromethane acishe abe ziro.

Ama-micropores asekelwe kusihlukanisi se-MOF awukhiye ngoba lawa ma-micropores angagcina ama-electrolyte amaningi egeleza ebhethrini ngisho nangaphansi kwengcindezi encishisiwe. I-diaphragm yokuhweba inezimbotshana ezinkulu futhi ayikwazi ukugcina ama-molecule e-electrolyte egesi ngaphansi kwengcindezi encishisiwe. Kodwa i-microporosity akuyona ukuphela kwesizathu sokuthi i-diaphragm isebenza kahle ngaphansi kwalezi zimo. I-diaphragm eklanywe abacwaningi iphinde ivumele ama-pores ukuba enze indlela eqhubekayo ukusuka komunye umkhawulo kuya komunye, ngaleyo ndlela iqinisekise ukuthi i-lithium ion ingageleza ngokukhululekile nge-diaphragm. Ekuhlolweni, ukuqhutshwa kwe-ionic kwebhethri kusetshenziswa i-diaphragm entsha ku-40°C kuphindwe kashumi kunebhethri esebenzisa i-diaphragm yezentengiso.

Ithimba lika-Chen okwamanje lihlola izihlukanisi ezisekelwe ku-MOF kwamanye ama-electrolyte. U-Chen uthe: "Sibone imiphumela efanayo. Ngokusebenzisa le MOF njenge-stabilizer, ama-molecule e-electrolyte ahlukahlukene angakhangiswa ukuze kuthuthukiswe ukuphepha kwebhethri, okuhlanganisa amabhethri e-lithium endabuko anama-electrolyte aguquguqukayo."