LiFePO4 kye ki mu bbaatule za lithium??
Enyanjula ku Bikozesebwa mu Lithium Iron Phosphate
Lithium iron phosphate (ensengekera ya molekyu LiFePO4, lithium iron phosphate, LFP, era emanyiddwa nga lithium iron phosphate oba ferrous lithium phosphate) kintu kya katodi ekikozesebwa mu bbaatule za lithium-ion. Engeri zaayo kwe kuba nti temuli bintu bya muwendo nga cobalt oba nickel, bbeeyi y’ebintu ebisookerwako eri wansi; era kaboni, litiyamu, n’ekyuma biri mu bungi mu kibumba ky’ensi, ebisobola okutuukiriza obwetaavu bw’akatale obwa ttani ezisukka mu bukadde bumu buli mwaka. Nga ekintu kya katodi, lithium iron phosphate erina vvulovumenti y’okukola ey’ekigero (3.2 V), obusobozi obw’enjawulo obw’amaanyi (170 mA·h/g), amaanyi ag’okufulumya amangi, obusobozi bw’okucaajinga amangu, n’obulamu obuwanvu obw’enzirukanya, ng’erina okutebenkera okulungi mu mbeera ez’ebbugumu eringi-n’ebbugumu eringi-.
Ekiristaalo kya lithium iron phosphate kiri mu kika kimu eky’ensengekera ya olivine. Mu by’obuggagga bw’omu ttaka, kituumibwa triphylite, nga kiva mu kigambo ky’Oluyonaani emirandira gya tri ne lylon. Mu ores, langi eyinza okuba enzirugavu, emmyufu-kitaka enzirugavu, kitaka, oba ekiddugavu, ate ebivaamu ebituufu biba biddugavu oba enzirugavu-ebiddugavu. Ebintu ebimu eby’obutonde ebirimu lithium iron phosphate, naye ekigero kyayo kitono era tekituuka ku ddaala lya kukozesebwa mu nkola. Lithium iron phosphate eri mu kiti kya phosphate ekigatta, era ensengekera yaayo ey’eddagala eya bulijjo erina okuba LiMPO4, nga M esobola okuba ekyuma kyonna eky’enjawulo, omuli Fe, Co, Mn, Ti, n’ebirala Olw’okuba kkampuni eyasooka okutunda LiMPO4 yakola lithium iron phosphate, abantu bamanyidde okukwata lithium iron phosphate ng’ekintu kyokka ekigatta phosphate cathode. Naye ku bikozesebwa ebirina ensengekera ya olivine, lithium iron phosphate si ye yokka eyinza okukozesebwa ng’ekintu kya katodi mu bbaatule za lithium-ion. Okusinziira ku kumanya okuliwo kati, waliwo ne LiMnPO4, LiMnFePO4, LiVPO4, LiCoPO4, n’ebintu ebirala bingi.
Ensibuko y’ebintu bya lithium iron phosphate esobola okuddirira mu 1996, kkampuni y’amasimu eya Japan NTT lwe yasooka okuzuula nti AMPO4 (A kyuma kya alkali, M ye Co oba Fe) ekirina ensengekera ya olivine, mu kugatta LiFeCoPO4, kisobola okukozesebwa ng’ekintu kya lithium-ion battery cathode. Oluvannyuma, kyazuulibwa ekibiina ky’abanoonyereza ekya Goodenough mu Massachusetts Institute of Technology mu Amerika, nga basoma ebirungo ebikola, nti ekintu kya lithium iron phosphate kirina eky’obugagga ekikyukakyuka eky’okuyingiza n’okuggyamu lithium-ion (Li+). Nga April 23, 1997, Yunivasite y'e Texas e Austin yawaaba patent eyatuumiddwa "Cathode materials for rechargeable lithium secondary batteries" (WO1997010541), nga kino kyatandikawo obwannannyini bwa patent ku bintu bya lithium iron phosphate.
Okufulumya ebintu bya olivine-structured phosphate (LiMPO4) cathode mu kiseera kye kimu Amerika ne Japan kwasikiriza nnyo okufaayo, kwaleetawo okunoonyereza okunene, era ne kugenda mu maaso mangu enkola y’okukulaakulanya amakolero. Bw’ogeraageranya n’ebintu eby’ennono ebya lithium-ion secondary battery cathode materials-spinel-structured lithium manganese oxide (LiMn2O4) ne layered-structured lithium cobalt oxide (LiCoO2)-LiMPO4 erina ebintu ebisookerwako ebisinga okubeerawo ennyo era eby’ebbeeyi entono nga tebirina butonde obucaafu. Okusingira ddala, obukuumi bulongooseddwa nnyo, ekireeseewo okwagala okunene okuva mu banoonyereza n’amakolero.
Okusinziira ku bivudde mu kunoonyereza mu myaka egiyise, ekintu kya lithium iron phosphate kirina ensengekera ya olivine ekoleddwa obulungi-crystallized, era emikutu gyakyo egy’okusaasaana kwa lithium-ion gyawukana ku egy’ebintu bya cathode eby’ennono. Ebintu bya katodi eby’ennono birina ensengekera za layeri oba spinel, ekisobozesa ion za lithium okutambula amangu wakati wa layers oba mu mikutu eminene, bwe kityo ne kiwa ebintu omulimu omulungi ogw’okufulumya. Okwawukana ku ekyo, emikutu gy’okusaasaana kwa lithium-ion mu bintu bya lithium iron phosphate gya kimu-dimensional, ekitegeeza nti munda mu kirisitaalo mulimu "tunnel" yokka ey'okusaasaana kwa lithium-ion, kale omutindo gw'okutambula kwa lithium-ion gugenda mpola nnyo era ebanga ly'okusaasaana liri ttono. Naddala mu mbeera z’okufuluma kw’omutindo ogwa waggulu-, ion za lithium ez’omunda teziyinza kusenguka kufuluma mu budde, ekivaamu okuwunyiriza kw’amasannyalaze okw’amaanyi.
Battery zisobola okukolebwa nga tukozesa ekintu ekirongoofu ekya lithium iron phosphate okukakasa ebyo waggulu. Okugezesa kulaga nti obusobozi bw’okukozesa ekintu ekirongoofu ekya lithium iron phosphate butono nnyo, era bbaatule efuna okuvunda okw’amangu okw’obusobozi mu kiseera ky’okuvuga obugaali. Ekifaananyi 2.1 kiraga enkola y’enzirukanya y’obutoffaali bwa lithium-ion coin cell eyakolebwa omuwandiisi ng’akozesa hydrothermally synthesized pure lithium iron phosphate (nga tewali kizigo kya kaboni). Kiyinza okulabibwa nti oluvannyuma lw’enzirukanya ya charge–discharge nga 15, obusobozi bwa bbaatule buvunze ebitundu ebisukka mu 20%. N’olwekyo, ekintu ekirongoofu ekya lithium iron phosphate tekisaanira nkola za bbaatule za lithium-ion.
Mu mwaka gwa 2000, Hydro-Québec (H-Q), ekitongole kya gavumenti eky’eggwanga ekya Canada, kye kyasooka okuteeka mu fayiro patent ku kusiiga lithium iron phosphate n’ebintu ebitambuza, omuli n’okukozesa carbon okusiiga ku bintu bya lithium iron phosphate. Kino kyasobozesa lithium iron phosphate okutuuka ku busobozi obw’enjawulo obw’amaanyi era ne kyongera ku bulamu bwayo obw’enzirukanya okutuuka ku nsengekera ezisukka mu 2000. Kino kye kyatandika enkola y’okukulaakulanya amakolero mu lithium iron phosphate ng’ekintu kya katodi.
