Chemistry Week 2021: How Chemistry Is Driving Sustainability Through Electric Vehicle Battery Technology - New Technology - Technology (2024)

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The Royal Society of Chemistry (RSC) has opted to holdits annual Chemistry Week this year on 1-12 November 2021, tocoincide with the 26th UN Climate Change Conference of the Parties(COP26). To reflect and celebrate themes that span both COP26 andthe RSC's Chemistry, Sustainability and Circular Economy (CSCE)campaign, the society has chosen 'sustainability' as thefocus of Chemistry Week 2021. With this in mind, we are marking theevent with an article celebrating how chemists are driving forwardsustainability in the automotive sector.

As announced by the government in November2020, the UK will phase out the sale of new petrol anddiesel-powered cars by 2030, with many other countries followingsimilar roadmaps. Such efforts will put huge pressure on theelectric vehicle (EV) market to provide alternative vehicles thatare convenient, reliable and cost-effective. Theenginesleading these efforts are the chemists, harnessing allthe expertise of their field to revolutionise the automotiveindustry.

As the world faces the climate change crisis, its historicreliance on fossil fuels in powering the approximately 1.4 billionvehicles in use globally (as of 2021) is becoming increasinglyunsustainable. Alternate means of fuelling our vehicles must befound, and, having gained considerable momentum over the past fewyears, EVs are at the forefront of these efforts.

The classification of EVs encompasses a broad field, includingvehicles powered by fuel cells, solar cells and batteries, but theyare all united by the fundamental importance of chemistry ingoverning their efficacy. The most popular type of electric vehiclerelies on its onboard battery to store chemical energy that can betransformed into electrical power. This battery is a crucialelement in the operation of such EVs, and extensive research isbeing conducted globally to find compounds – and theircombinations – with the most advantageous chemical propertiesthat can bring about the next revolution in battery technology.According to ajoint European Patent Office (EPO) andInternational Energy Agency (IEA) study, patenting activity ofbattery technologies grew at an average annual rate of 14% between2005 and 2018. Currently, the most abundant type of battery is theone that helped kick-start fully electric vehicles: the lithium-ion(Li-ion) battery.

The first patent for a Li-ion battery in its modern form wasfiled in 1983, by Professor Akira Yoshino while working for thecompany Asahi Kasei. This helped them to control 17% of the globalmarket share for Li-ion battery separators until 2016. Sony,alongside Asahi Kasei, later went on to commercialise the firstLi-ion battery product in 1991, protected by the security affordedby their patents. By 2015, they had shipped over five billion cellsand pioneered a revolution in modern battery technology.

While the Li-ion battery was a huge step forward in batterytechnology – providing much higher charge density andeffective rechargeability – within the context of EVs, thereare still many limitations to overcome, with capacity being aprominent example. The average range of a fully charged EV (acrossthe spectrum of manufacturers) is around 300km, with many beingsignificantly lower. However, an understanding of the chemicalproperties that give rise to this limitation – namely thestorage density of lithium atoms within the electrode materials– has allowed researchers to develop promisingalternatives.

One such example is a prototype lithium-sulfur battery with thepotential to more than double the specific energy (energy per unitmass) of Li-ion batteries. This innovation is based on replacingthe cobalt-based cathode material with one comprised of S8 sulfur.As Li-ions and electrons converge at this cathode during discharge,a series of sequential reactions eventually reduce the octatomic S8to eight individual sulfur atoms each bonded to two lithium atoms.In this way, each sulfur atom within the cathode can accommodatetwo Li-ions, in comparison with the roughly 0.6 Li per host atomsthat conventional Li-ion batteries achieve. However, many otheralternative solutions are being explored, such as the use ofnickel, phosphates, and manganese, hinting that there is stillspace for innovation in this field.

The speed at which an EV can be charged is also a cruciallimitation, with serious consequences for public adoption of fullyelectric vehicles if not suitably resolved; who wants to spendseven+ hours recharging their car when they forgot to charge itovernight, or take half an hour for a 'quick' top up justto get them home? While there are certainly vast infrastructureimprovements to be made to alleviate some of this concern,chemistry still has plenty to offer on this front too. Thisresearch is primarily focused on the anode and electrolyte, asthese are where the rate-limiting steps in the charging processoccur. Regarding the anode, the theoretically superior propertiesof silicon (such as its 10-fold higher specific capacity) have madeit a widely studied material. For example, it is the basis of anupcoming EV battery that claims to achieve five-minute chargingtimes.

The chemistry of electrolytes is also making significantcontributions towards resolving these issues. While conventionalLi-ion batteries make use of liquid electrolytes, consisting oflithium salts in various organic solvents, many are turning theirattention to the benefits solid-state electrolytes could provide(such as greater energy density and improved safety). Examples suchas certain lithium metal oxides exist as a crystalline lattice thatcan possess extremely high ionic conductivity, permitting the rapidmovement of lithium ions between the electrodes. Efforts being madetowards the successful development of these solid-state batteriescan be demonstrated by the fact that automotivemanufacturerToyota reportedly holds over 1,000 patents inthe field. Nonetheless, there undoubtedly remains a wealth ofopportunity across the entire field of battery development for thediscovery of the next transformative breakthrough.

New technologies, even those as groundbreaking as the Li-ionbattery, can take upwards of 20 years to successfullycommercialise, so ensuring that you are able to exploit yourinvention to fully reap the rewards of your work and investment isimportant. Patents are an invaluable tool in protecting yourintellectual property, giving you control over how your ideas areused.

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