Dɛn ne LiFePO4 wɔ lithium battery mu??
Nnianim asɛm a ɛfa Lithium Iron Phosphate Nneɛma ho
Lithium dade phosphate (molekyule nhyehyɛe LiFePO4, lithium dade phosphate, LFP, a wɔsan frɛ no lithium dade phosphate anaa ferrous lithium phosphate) yɛ cathode ade a wɔde di dwuma wɔ lithium-ion batere mu. Ne su ne sɛ enni nneɛma a ɛsom bo te sɛ cobalt anaa nickel, nneɛma a wɔde yɛ no bo sua; na carbon, lithium, ne dade dɔɔso wɔ asase no mu, na ebetumi adi gua so ahwehwɛde bɛboro tɔn ɔpepem biako afe biara. Sɛ́ cathode ade no, lithium iron phosphate wɔ adwumayɛ ahoɔden a ɛkɔ fam (3.2 V), tumi pɔtee a ɛkorɔn (170 mA·h/g), ahoɔden a ɛkɔ soro a ɛtwetwe, tumi a ɛbɔ ntɛmntɛm, ne nkwa nna tenten, a ɛgyina pintinn yiye wɔ mmeae a ɛhɔ yɛ hyew kɛse ne ɔhyew a ɛkɔ soro-mu.
Lithium iron phosphate ahwehwɛ no yɛ olivine nhyehyɛe bi dea. Wɔ aboɔden abo ho adesua mu no, wɔto din triphylite, a wonya fii Hela asɛmfua ntini tri ne lylon mu. Wɔ ores mu no, kɔla no betumi ayɛ tuntum, kɔkɔɔ-brown grey, brown, anaa tuntum, bere a nneɛma ankasa yɛ tuntum anaa grey-tuntum. Lithium iron phosphate wɔ abɔde mu nneɛma bi a wɔde yɛ aboɔden abo mu, nanso ne dodow sua na entumi nkɔ baabi a wobetumi de adi dwuma yiye. Lithium iron phosphate ka phosphate a wɔabom ayɛ no fã, na ɛsɛ sɛ ne nnuru a wɔde yɛ no nyinaa yɛ LiMPO4, baabi a M betumi ayɛ dade biara a ɛwɔ divalent, a Fe, Co, Mn, Ti, ne nea ɛkeka ho ka ho Esiane sɛ adwumakuw a edi kan a ɛde LiMPO4 dii gua no yɛɛ lithium iron phosphate nti, nkurɔfo abɛyɛ wɔn su sɛ wɔbɛyɛ lithium iron phosphate sɛ phosphate cathode ade biako pɛ a wɔabom ayɛ. Nanso, wɔ nnuru a ɛwɔ olivine nhyehyɛe no fam no, ɛnyɛ lithium iron phosphate nkutoo na wobetumi de adi dwuma sɛ cathode ade wɔ lithium-ion batere mu. Sɛnea mprempren nimdeɛ kyerɛ no, LiMnPO4, LiMnFePO4, LiVPO4, LiCoPO4, ne nneɛma afoforo pii nso wɔ hɔ.
Yebetumi ahu sɛnea lithium iron phosphate nneɛma fi bae no fi 1996, bere a Japan telefon so nkitahodi adwumakuw NTT dii kan hui sɛ AMPO4 (A yɛ alkali dade, M yɛ Co anaa Fe) a ɛwɔ olivine nhyehyɛe, a wɔde LiFeCoPO4 a wɔaka abom no, wobetumi de adi dwuma sɛ lithium-ion battery cathode ade. Akyiri yi, Goodenough nhwehwɛmu kuw a ɛwɔ Massachusetts Institute of Technology a ɛwɔ United States no hui, bere a na wɔresua nneɛma a wɔde yɛ nhyehyɛe ho ade no, sɛ lithium dade phosphate nneɛma wɔ su a wotumi dannan a ɛne lithium-ion (Li+) a wɔde hyɛ mu ne nea wɔde hyɛ mu. Wɔ April 23, 1997 mu no, Texas Sukuupɔn a ɛwɔ Austin no de tumi krataa a wɔato din "Cathode materials for rechargeable lithium secondary batteries" (WO1997010541) kɔe, na ɛhyɛɛ tumi krataa a ɛwɔ lithium iron phosphate nneɛma ho no ase.
Olivine-structured phosphate (LiMPO4) cathode nneɛma a United States ne Japan tintimii bere koro mu no twee adwene kɛse, ɛkanyan nhwehwɛmu kɛse, na ɛmaa mfiridwuma mu nkɔso nhyehyɛe no nyaa nkɔso ntɛmntɛm. Sɛ wɔde toto atetesɛm mu lithium-ion secondary battery cathode nneɛma-spinel-structured lithium manganese oxide (LiMn2O4) ne layered-structured lithium cobalt oxide (LiCoO2){6}}LiMPO4 wɔ raw materials a ɛwɔ hɔ kɛse na ne bo yɛ mmerɛw a enni nneɛma a atwa yɛn ho ahyia efĩ a ɛba. Titiriw no, wɔama ahobammɔ atu mpɔn kɛse, na akanyan nhwehwɛmufo ne nnwumayɛfo anigye kɛse.
Sɛnea nhwehwɛmu a efii mu bae wɔ nnansa yi mfe mu kyerɛ no, lithium iron phosphate ade no wɔ olivine nhyehyɛe a ɛyɛ ahwehwɛ yiye, na ne lithium-ion trɛw akwan no yɛ soronko wɔ nea ɛwɔ atetesɛm cathode nneɛma mu no ho. Cathode nneɛma a wɔde di dwuma wɔ amanne kwan so no wɔ layers anaa spinel structures, na ɛma lithium ions tumi tu ntɛmntɛm wɔ layers ntam anaasɛ wɔ akwan akɛse mu, na ɛnam so ma nneɛma no nya discharge adwumayɛ pa. Nea ɛne eyi bɔ abira no, lithium-ion trɛw akwan a ɛwɔ lithium dade phosphate nneɛma mu no yɛ biako-afã, a ɛkyerɛ sɛ wɔ ahwehwɛ no mu no, "tunnel" nkutoo na ɛwɔ hɔ ma lithium-ion trɛw, enti lithium-ion tu a ɛkɔ baabi foforo no yɛ brɛoo na ntrɛwmu kwan no yɛ tiaa. Titiriw wɔ high-rate discharge tebea horow mu no, lithium ions a ɛwɔ mu no ntumi nkɔ abɔnten wɔ bere mu, na ɛde electrochemical polarization kɛse ba.
Wobetumi de lithium dade phosphate a ɛho tew ayɛ batere de ahwɛ sɛ nea yɛaka wɔ atifi hɔ no yɛ nokware. Nsɔhwɛ ahorow ada no adi sɛ tumi a wɔde di dwuma wɔ lithium dade phosphate a ɛho tew mu no sua koraa, na batere no tumi porɔw ntɛmntɛm bere a wɔde sakre retu kwan no. Mfonini 2.1 kyerɛ sɛnea lithium-ion sika nkwammoaa a ɔkyerɛwfo no de hydrothermally synthesized pure lithium iron phosphate (a enni carbon coating) yɛɛ no kyinhyia adwumayɛ. Yebetumi ahunu sɛ wɔ bɛyɛ 15 charge–discharge cycles akyi no, battery no ahoɔden asɛe bɛboro 20%. Enti, lithium dade phosphate a ɛho tew no mfata mma lithium-ion batere nhyehyɛe.
Wɔ afe 2000 mu no, Hydro-Québec (H-Q), Canada ɔman ɔmanfo adwumayɛbea, na edi kan de tumi krataa kɔe sɛ wɔde nneɛma a ɛma nsu fa mu bɛkata lithium iron phosphate so, a carbon a wɔde kata lithium iron phosphate nneɛma so ka ho. Eyi maa lithium iron phosphate tumi nyaa tumi pɔtee a ɛkorɔn na ɛmaa ne kyinhyia nkwa nna trɛw kɔɔ bɛboro kyinhyia 2000. Eyi na wofii mfiridwuma mu nhyehyɛe a wɔde yɛɛ lithium iron phosphate sɛ cathode ade no mfiase.
