Dɛn Ne Battery Tumi a Ɛsɛe Ade?
Nsakrae a Ɛba Nneɛma a Wɔde Yɛ Adwuma Mu
Mprempren cathode nneɛma a wɔde di dwuma kɛse no titiriw ne LiMO2 a ɛyɛ ahinanan a ɛwɔ ntoatoaso (beae a M=Co, Ni, Mn), LiMn2O4 spinel nhyehyɛe, ne LiFePO4 olivine nhyehyɛe. Ɛmfa ho sɛnea wɔahyehyɛ no, sɛ lithium ions fi cathode no mu, sɛnea ɛbɛyɛ a anyinam ahoɔden tebea a ɛwɔ ade no mu no akɔ so atra hɔ no, akyinnye biara nni ho sɛ dade ade no yɛ oxidized kɔ valence tebea a ɛkorɔn mu, a phase nsakrae nhyehyɛe ka ho. Phase nsakrae taa ma phase nsakrae ba, enti bere a lithium ions kɔ so hyɛ mu na ɛtwetwe wɔ ade no mu no, fase nsakrae no kɔ so, na bere tenten mu no, ɛde asiane bɛto ahwehwɛ no a ɛbɛkɔ so agyina pintinn no so. Sɛ wɔde toto anode no ho a, tumi a ɛnyɛ pɛ a wotumi dannan no a ɛnam phase shifts ne nsakrae a ɛba wɔ cathode ade no nhyehyɛe kɛse mu no nya nkɛntɛnso kɛse wɔ battery nkwa so. Graphite wɔ nhyehyɛe a ɛwɔ ntoatoaso. Sɛ ɛyɛ ntoatoaso pii a, lithium ions kɔhyɛ ntamadan no mu bere a batere no rebɔ no na ɛne ɛlɛtrɔnik a wɔde fi abɔnten kwansin no mu kɔ no bom yɛ lithiated graphite, na ntam kwan a ɛda ntam no kɔ soro saa bere yi; bere a ɛrepue no, lithium ions fi graphite ntam nhama no mu na ɛma ɛlɛtrɔnik kɔ abɔnten kwan no mu, na ɛkɔ deintercalation ne oxidation adeyɛ mu, na ntam kwan a ɛda ntam no so tew wɔ saa bere yi mu.
Nneɛma a Ɛyɛ Adwuma a Wɔpete
Cathode nneɛma a wɔpete no kyerɛ adeyɛ a ade a ɛyɛ adwuma no so tew nkakrankakra esiane nsɛe a ɛwɔ electrolyte no mu nti. Cathode nneɛma a wɔpete wɔ ɔhyew a ɛkɔ soro mu no yɛ ade biako nti a batere ahoɔden sɛe, titiriw no, ɛwɔ nkɛntɛnso kɛse wɔ batere ahorow no kyinhyia adwumayɛ ne sɛnea wɔkora so wɔ ɔhyew a ɛkɔ soro mu. Nsakraeɛ dadeɛ a wɔpete wɔ tebea bi mu no yɛ ɔhaw a ɛwɔ LiMO2 cathode nneɛma nyinaa mu. Nneɛma titiriw nti a nneɛma a ɛyɛ adwuma a wɔpete no ma batere no adwumayɛ sɛe ne: $\\textcircled{1}$ Dade nneɛma a wɔpete no ma nneɛma a ɛyɛ adwuma no so tew tẽẽ, na ɛma batere ahoɔden hwere; $\\textcircled{2}$ Cathode nneɛma a ɛpete no ma nneɛma no nhyehyɛe sɛe na nneɛma a nnuru ntumi nyɛ adwuma wɔ nneɛma nketenkete no ani, na ɛno siw lithium ions a ɛkɔ electrode ade no mu no kwan $\\textcircled{3}$ Dadeɛ ions a wɔabɔ no aduru a ɛwɔ electrolyte no mu no tu kɔ anode a ɛwɔ electrolyte no mu no kɔ anode no ani wɔ anode no ani wɔ dadeɛ anaa nkyene kwan so wɔ tumi a ɛba fam ase, na akyinnyeɛ biara nni ho sɛ saa nneɛma a ɛwɔ hɔ yi nya SEI film a ɛwɔ anode no ani no gyinabea ne ne kɛseɛ so nkɛntɛnsoɔ, na ɛma electrode no ani polarization kɔ soro na battery no mu ahoɔden a ɛko tia no kɔ soro. Enti, ɛnyɛ nsunsuanso a nneɛma a ɛyɛ nnam a wɔpete no nya wɔ electrolyte no so no fi nsunsuanso nko na mmom efi nkɛntɛnso bɔne kɛse a nsakrae dade a wɔpete de ba nso.
Lithium Ion a Wɔde Di Dwuma
Wɔ lithium-ion batere nhyehyɛɛ mu no, mpɛn pii no, battery no tumi boro cathode no de so kakra, na lithium ions a wotumi de di dwuma bio no nso cathode no na ɛde ma. Enti, lithium ions a wotumi dannan no intercalation ne deintercalation a ɛda cathode ne anode ntam no na ɛkyerɛ battery no tumi. Wɔ charge ne discharge adeyɛ a edi kan no mu no, wɔyɛ SEI film wɔ anode no ani. Nneɛma titiriw a ɛwɔ saa passivation film yi mu ne nneɛma ahorow a ɛnyɛ abɔde te sɛ Li2CO3, LiF, Li2O, LiOH ne nneɛma ahorow a nkwa wom te sɛ ROCO2Li, RLi, ne (ROCO2)2Li. Enti, wɔsɛe lithium ions bi, na tumi a wɔhwere yi yɛ nea wontumi nsakra. Anode no adwumayɛ ne SEI sini no nsɛsoɔ ne ne gyinabea wɔ abusuabɔ kɛseɛ, na tumi a ɛtumi yɛ SEI sini a ɛgyina pintinn wɔ anode no ani no wɔ nkɛntɛnsoɔ a ɛnyɛ-nea ɛnyɛ hwee wɔ battery adwumayɛ so. SEI sini no a wɔhyehyɛ no di lithium ions kakraa bi a ɛwɔ batere no mu no. Sɛ SEI film no kɔ so sɛe wɔ kyinhyia no mu a, ɛnde oxidation reaction a ɛwɔ anode/electrolyte ntam no bɛkɔ so aba ma ayɛ SEI film foforo. Saa adeyɛ yi di lithium ions kakraa bi a cathode a ɛwɔ nhyehyɛe no mu de ma no, na lithium ions a ɛyɛ adwuma a ɛso tew no ma tumi no sɛe. Lithium ions a ɛwɔ electrolyte no mu a ɛso tew no ma electrolyte no tumi a ɛkɔ so no so tew, na lithium ions a ɛyera wɔ cathode ade no mu no ma battery no electrode abien no ntumi nkari pɛ.
Nkɔanim a ɛba wɔ Mfinimfini Nkonimdi mu
Wɔ bere tenten-a batere no kyinhyia mu no, nkɔanim a ɛba wɔ emu ahoɔden a ɛko tia no nso yɛ ade titiriw a ɛma tumi no sɛe. Nneɛma pii nti na emu ahoɔden a ɛko tia no kɔ soro, titiriw fi afã abien: $\\textcircled{1}$ Oxidation adeyɛ a ɛkɔ so wɔ electrode/electrolyte ntam wɔ electrolyte no mu no ma electrode no soro film resistance no kɔ soro, ne anode SEI film no a entumi nnyina pintinn, a ɛkɔ so yɛ soro films foforo wɔ kyinhyia no mu, ne nea ɛkeka ho, ne nyinaa ma polarization ne battery kɔ soro wɔ resistance no mu $\\textcircled{2}$ Dadeɛ ions a ɛwɔ cathode no mu a ɛpete kɔ electrolyte no mu, ne dadeɛ ions a wɔapete no fa electrolyte no mu tu kɔ anode no so na ɛkɔ anode no ani wɔ dadeɛ anaa nkyene mu, na ɛma electrode polarization kɔ soro. Bio nso, nhwehwɛmu nso ada no adi sɛ mprempren ade a wɔboaboa ano no nsɛe nso betumi ama emu ahoɔden a ɛko tia no akɔ soro, nanso saa nkɛntɛnso yi sua koraa wɔ adwene a ɛne sɛ wɔadi kan ayɛ mprempren ade a wɔboaboa ano no ho adwuma no ase. Nkɔanim a ɛba wɔ emu ahoɔden mu no ma ahoɔden dodow ne tumi so tew, titiriw ma anode no, adeyɛ a ɛkɔ so wɔ electrode/electrolyte ntam no ne ade titiriw nti a anode no nyin.
