Lithium breakthrough: Poms discover why nickel cathodes in batteries degrade and how to fix it
Brit scientists have made a ‘significant breakthrough’ in understanding – and overcoming – the challenges associated with the loss of oxygen in nickel-rich cathode materials which form the guts of your standard lithium-ion batteries.
It’s these nickel friendly materials that wrap around the er, lithium intestines and which scientists at the Unis of Cambridge and of Birmingham believe have the potential to achieve both high voltages and capacities if their use in practical applications were not hindered by structural instabilities and loss of oxygen.
Currently 39% of Li-ion batteries contain nickel. This is expected to rise to around 58% by 2025, according to the Nickel Peak Body, which I think is just called: Nickel.
They say nickel in the battery provides higher energy density and storage at lower cost.
Their study revealed that ‘oxygen hole’ formation – where an oxygen ion loses an electron – plays a crucial role in the degradation of LiNiO2 cathodes accelerating the release of oxygen which can then further degrade the cathode material.
Using the Poms’ “state-of-the-art” computational techniques on UK regional supercomputers, the researchers examined the behaviour of LiNiO2 cathodes as they get charged. The researchers found that during charging, the oxygen in the material undergoes changes while the nickel charge remains essentially unchanged.
Here’s co-author Professor Andrew J. Morris, from the University of Birmingham:
“We found that the charge of the nickel ions remains around +2, regardless of whether it’s in its charged or discharged form. At the same time the charge of the oxygen varies from -1.5 to about -1.
“This is unusual, the conventional model assumes that the oxygen remains at -2 throughout charging, but these changes show that the oxygen is not very stable, and we have found a pathway for it to leave the nickel-rich cathode.”
The researchers compared their calculations with experimental data and found that their results aligned well with what was observed.
They proposed a mechanism for how oxygen is lost during this process, involving the combination of oxygen radicals to form a peroxide ion, which is then converted into oxygen gas, leaving vacancies in the material.
This process apparently releases energy and forms singlet oxygen, a highly reactive form of oxygen.
Gone for good, it seems, are the days when the most crucial use of nickel was for making long-lasting 50 cent pieces.
Nickel’s also handy for plating stuff to make it cooler (ok, and harder) as well as for making lots of wires. It gets used in gas turbines and rocket engines a fair bit – as it has the capability to resist corrosion even at high temperatures. Also handy – nickel for whipping up a variety of alloys which can find their way into your armour plated Tesla, as well as some nails, or pipes.
I’ve seen dimes worth more than nickel.
That’ll change. According to something I read a year or so back, some 50kg of nickel goes into each Tesla battery.
Topline author Dr Annalena Genreith-Schriever from the University of Cambridge says:
“Potentially, by adding dopants that reduce oxygen redox, while promoting transition-metal redox particularly at the surface, mitigating the generation of singlet oxygen, we can enhance the stability and longevity of these type of lithium-ion batteries, paving the way for more efficient and reliable energy storage systems.”
In plain speak, that means that the boffins think they have figured out a way to mitigate if not outright prevent the degradation of nickel cathodes, potentially increasing their overall performance and lifespan.
This is likely to be welcome given that lithium-ion batteries are widely used for various applications because of their high energy density and rechargeability.
Researchers from the Universities of Birmingham, Cambridge, Warwick as well as The Faraday Institution, Didcot, published their findings on Wednesday 19 July in Joule Magazine.
Lithium Breakthrough: Poms kugundua kwa nini nickel cathodes katika betri kuharibika na jinsi ya kurekebisha ni. wanasayansi wa Uingereza wamefanya 'kufanikiwa muhimu' katika kuelewa na kushinda changamoto zinazohusiana na hasara ya oksijeni katika nyenzo nickel-tajiri cathode ambayo fomu matumbo ya betri yako ya kawaida lithiamu-ion. Ni nyenzo hizi za rafiki za nikeli ambazo hufunika matumbo ya lithiamu na ambayo wanasayansi katika Chuo Kikuu cha Cambridge na Birmingham wanaamini kuwa na uwezo wa kufikia voltage na uwezo wa juu ikiwa matumizi yao katika matumizi ya vitendo hayakuzuiwa na kutoelewana kwa muundo na upotezaji wa oksijeni. Kwa sasa, asilimia 39 ya betri za Li-ion zina nikeli. "Kama ilivyoelezwa katika ripoti ya ""Nickel Peak Body,"" kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango cha kiwango." Ni kwamba nikeli katika betri hutoa nguvu zaidi na kuhifadhi kwa gharama ya chini. Utafiti wao ulifunua kwamba uundaji wa "shimo la oksijeni" - ambapo ion ya oksijeni hupoteza elektroni - una jukumu muhimu katika uharibifu wa cathodes za LiNiO2 kuharakisha kutolewa kwa oksijeni ambayo inaweza kuharibu zaidi nyenzo ya cathode. Kwa kutumia mbinu za kompyuta za hali ya juu za POM, watafiti walichunguza tabia ya katodi za LiNiO2 zinapopigwa. Watafiti walipata kwamba wakati wa kuchaji, oksijeni katika nyenzo hupitia mabadiliko wakati malipo ya nikeli hubaki bila kubadilika. "Profesa Andrew J. Morris, kutoka Chuo Kikuu cha Birmingham, alisema: ""Tumegundua kwamba malipo ya ioni za nikeli hubaki karibu +2 bila kujali ikiwa ni katika fomu yake ya malipo au ya kutolewa." Wakati huo huo malipo ya oksijeni inatofautiana kutoka -1.5 hadi karibu -1. "Mfano wa kawaida unadhani kwamba oksijeni inabaki katika -2 wakati wote wa kuchaji, lakini mabadiliko haya yanaonyesha kwamba oksijeni haijulikani kuwa imara sana, na tumepata njia ya kuondoka kwa cathode yenye nickel. "" Watafiti walilinganisha hesabu zao na data ya majaribio na kugundua kuwa matokeo yao yalipatana vizuri na yale yaliyotambuliwa." "Wanachunguza jinsi oksijeni inavyopotea wakati wa mchakato huu, ikihusisha mchanganyiko wa mizizi ya oksijeni kuunda ion ya peroxide, ambayo kisha hubadilishwa kuwa gesi ya oksijeni, na kuacha nafasi katika nyenzo.""" Inaonekana kwamba mchakato huo hutokeza nishati na kutokeza oksijeni ya singlet, ambayo ni aina ya oksijeni inayoweza kuathiriwa sana. Ni siku za mwisho kwa ajili ya faida, inaonekana, ni siku wakati matumizi muhimu zaidi ya nikeli ilikuwa kwa ajili ya kufanya vipande vya muda mrefu 50 senti. Nickel pia ni rahisi kwa ajili ya plating mambo ya kufanya hivyo baridi (ok, na ngumu) kama vile kwa ajili ya kufanya mengi ya waya. Ni anapata kutumika katika turbines gesi na injini roketi haki kidogo <unk> kama ina uwezo wa kukabiliana na kutu hata katika joto la juu. Pia rahisi <unk> nickel kwa whipping up aina mbalimbali ya alloys ambayo inaweza kupata njia yao katika silaha yako plated Tesla, kama vile baadhi ya misumari, au mabomba. Nimeona senti zenye thamani zaidi ya senti. Hilo litabadilika. Kulingana na utafiti wa Tesla, kila betri ya Tesla ina uzito wa 50kg. "Annalena Gennadette-Schreiber, PhD, PhD, PhD, PhD, PhD, PhD, PhD, PhD, PhD, PhD, PhD, Daktari wa Utafiti wa Chuo Kikuu cha Cambridge anasema: ""Kwa kuongeza dopants ambayo hupunguza oksijeni redox, wakati wa kukuza redox ya chuma cha mpito, hasa juu ya uso, kupunguza kizazi cha oksijeni ya singlet, tunaweza kuongeza utulivu na maisha ya aina hii ya betri ya lithiamu-ion, kuandaa njia ya mifumo ya kuhifadhi nishati ya ufanisi na ya kuaminika." Hii ni uwezekano wa kuwa kuwakaribisha kutokana na kwamba lithiamu-ion betri ni sana kutumika kwa ajili ya maombi mbalimbali kwa sababu ya wiani wao wa juu wa nishati na rechargeability. Watafiti kutoka Chuo Kikuu cha Birmingham, Cambridge, Warwick na Taasisi ya Faraday, Didcot, walichapisha matokeo yao Jumatano, Julai 19, katika jarida la Joule.