Silicon na tushen cathodes suna daidaita ƙwayoyin Li-S. Tasiri: fiye da 2 cajin hawan keke maimakon dozin da yawa

Masana kimiyya daga Cibiyar Kimiyya da Fasaha ta Daegu (DGIST, Koriya ta Kudu) sun ƙera wani cathode na silicon wanda ake sa ran zai iya jurewa fiye da 2 cajin hawan keke a cikin ƙwayoyin Li-S. Kwayoyin lithium-ion na al'ada suna amfani da siliki mai tsabta a cikin anodes don daidaitawa da maye gurbin graphite a hankali. An yi amfani da Silicon oxide a nan, kuma an yi amfani da silicon dioxide a cikin cathode.

Li-S cell = lithium anode, silicon dioxide cathode tare da sulfur

Kwayoyin Li-S ana ɗaukar su masu ban sha'awa saboda yawan ƙarfin kuzarinsu, nauyi da ƙarancin ƙira. Koyaya, har yanzu babu wanda ya sami nasarar ƙirƙirar sigar da zata jure fiye da dozin na caji. Duk saboda lithium polysulfides (LiPS), wanda ke narkewa a cikin electrolyte yayin fitarwa kuma yana amsawa tare da anode, yana rage ƙarfinsa kuma, sakamakon haka, lalata baturin.

Mai yiyuwa ne masu binciken Koriya ta Kudu sun sami mafita kan matsalar. Maimakon kayan da ke da carbon (kamar graphite), sun yi amfani da cathode. Tsarin lamellar mesoporous silica (POMS).

Tsarin lamellar yana iya fahimta, yayin da mesoporosity yana nufin tarawa na pores (cavities) a cikin silica wanda ke da girman maƙasudi, ƙananan yanki da ƙananan tarwatsawa (source). Yana da ɗan kama idan kuna yin turbaya ta cikin faranti kusa da wani nau'in siliki don yin sieve.

Masana kimiyya na DGIST sun yi amfani da waɗannan ramukan don saka sulfur a cikinsu (Hoto a). Lokacin fitarwa, sulfur yana narkewa kuma ya samar da lithium polysulfides (LiPS) tare da lithium. Don haka, cajin yana gudana, amma LiPS ya kasance a cikin tarko a kusa da cathode saboda ƙarin abubuwan da ba a bayyana ba (tsarin baƙar fata, adadi b).

Lokacin caji, LiPS yana fitar da lithium, wanda aka mayar da shi zuwa lithium anode. A gefe guda, sulfur yana canzawa zuwa siliki. Babu kwararar LiPS ga anode, babu lalacewar ƙarfe.

Batirin Li-S da aka ƙirƙira ta wannan hanya yana riƙe babban ƙarfi da kwanciyar hankali fiye da zagayowar aiki 2. Aƙalla 500-700 hawan keke na aiki ana ɗaukar daidaitattun ƙwayoyin Li-ion na al'ada, kodayake ya kamata a ƙara da cewa ƙwayoyin lithium-ion da aka sarrafa da kyau na iya jure hawan keke da yawa.