Three battery technologies that could power the future
The world needs more power, preferably in a form that’s clean and renewable. Our energy-storage strategies are currently shaped by lithium-ion batteries – at the cutting edge of such technology – but what can we look forward to in years to come?
Let’s begin with some battery basics. A battery is a pack of one or more cells, each of which has a positive electrode (the cathode), a negative electrode (the anode), a separator and an electrolyte. Using different chemicals and materials for these affects the properties of the battery – how much energy it can store and output, how much power it can provide or the number of times it can be discharged and recharged (also called cycling capacity).
Battery companies are constantly experimenting to find chemistries that are cheaper, denser, lighter and more powerful. We spoke to Patrick Bernard — Saft Research Director, who explained three new battery technologies with transformative potential.
NEW GENERATION LITHIUM-ION BATTERIES
What is it?
In lithium-ion (li-ion) batteries, energy storage and release is provided by the movement of lithium ions from the positive to the negative electrode back and forth via the electrolyte. In this technology, the positive electrode acts as the initial lithium source and the negative electrode as the host for lithium. Several chemistries are gathered under the name of li-ion batteries, as the result of decades of selection and optimization close to perfection of positive and negative active materials. Lithiated metal oxides or phosphates are the most common material used as present positive materials. Graphite, but also graphite/silicon or lithiated titanium oxides are used as negative materials.
With actual materials and cell designs, li-ion technology is expected to reach an energy limit in the next coming years. Nevertheless, very recent discoveries of new families of disruptive active materials should unlock present limits. These innovative compounds can store more lithium in positive and negative electrodes and will allow for the first time to combine energy and power. In addition, with these new compounds, the scarcity and criticality of raw materials are also taken into account.
What are its advantages?
Today, among all the state-of-the-art storage technologies, li-ion battery technology allows the highest level of energy density. Performances such as fast charge or temperature operating window (-50°C up to 125°C) can be fine-tuned by the large choice of cell design and chemistries. Furthermore, li-ion batteries display additional advantages such as very low self-discharge and very long lifetime and cycling performances, typically thousands of charging/discharging cycles.
When can we expect it?
New generation of advanced li-ion batteries is expected to be deployed before the first generation of solid state batteries. They’ll be ideal for use in applications such as Energy Storage Systems for renewables and transportation (marine, railways, aviation and off road mobility) where high energy, high power and safety is mandatory.
LITHIUM-SULFUR BATTERIES
What is it?
In li-ion batteries, the lithium ions are stored in active materials acting as stable host structures during charge and discharge. In lithium-sulfur (Li-S) batteries, there are no host structures. While discharging, the lithium anode is consumed and sulfur transformed into a variety of chemical compounds; during charging, the reverse process takes place.
What are its advantages?
A Li-S battery uses very light active materials: sulfur in the positive electrode and metallic lithium as the negative electrode. This is why its theoretical energy density is extraordinarily high: four times greater than that of lithium-ion. That makes it a good fit for the aviation and space industries.
Saft has selected and favoured the most promising Li-S technology based on solid state electrolyte. This technical path brings very high energy density, long life and overcomes the main drawbacks of the liquid based Li-S (limited life, high selfdischarge, …).
Furthermore, this technology is supplementary to solid state lithium-ion thanks to its superior gravimetric energy density (+30% at stake in Wh/kg).
When can we expect it?
Major technology barriers have already been overcome and the maturity level is progressing very quickly towards full scale prototypes.
For applications requiring long battery life, this technology is expected to reach the market just after solid state lithium-ion.
SOLID STATE BATTERIES
What is it?
Solid state batteries represent a paradigm shift in terms of technology. In modern li-ion batteries, ions move from one electrode to another across the liquid electrolyte (also called ionic conductivity). In all-solid state batteries, the liquid electrolyte is replaced by a solid compound which nevertheless allows lithium ions to migrate within it. This concept is far from new, but over the past 10 years – thanks to intensive worldwide research – new families of solid electrolytes have been discovered with very high ionic conductivity, similar to liquid electrolyte, allowing this particular technological barrier to be overcome.
Today, Saft Research & Development efforts focus on 2 main material types: polymers and inorganic compounds, aiming the synergy of the physico-chemical properties such as processability, stability, conductivity …
What are its advantages?
The first huge advantage is a marked improvement in safety at cell and battery levels: solid electrolytes are non-flammable when heated, unlike their liquid counterparts. Second, it permits the use of innovative, high-voltage high-capacity materials, enabling denser, lighter batteries with better shelf-life as a result of reduced self-discharge. Moreover, at system level, it will bring additional advantages such as simplified mechanics as well as thermal and safety management.
As the batteries can exhibit a high power-to-weight ratio, they may be ideal for use in electric vehicles.
When can we expect it?
Several kinds of all-solid state batteries are likely to come to market as technological progress continues. The first will be solid state batteries with graphite-based anodes, bringing improved energy performance and safety. In time, lighter solid state battery technologies using a metallic lithium anode should become commercially available.
How Lithium-ion Batteries Work
Lithium-ion batteries power the lives of millions of people each day. From laptops and cell phones to hybrids and electric cars, this technology is growing in popularity due to its light weight, high energy density, and ability to recharge.
So how does it work?
This animation walks you through the process.
The Basics
A battery is made up of an anode, cathode, separator, electrolyte, and two current collectors (positive and negative). The anode and cathode store the lithium. The electrolyte carries positively charged lithium ions from the anode to the cathode and vice versa through the separator. The movement of the lithium ions creates free electrons in the anode which creates a charge at the positive current collector. The electrical current then flows from the current collector through a device being powered (cell phone, computer, etc.) to the negative current collector. The separator blocks the flow of electrons inside the battery.
Charge/Discharge
While the battery is discharging and providing an electric current, the anode releases lithium ions to the cathode, generating a flow of electrons from one side to the other. When plugging in the device, the opposite happens: Lithium ions are released by the cathode and received by the anode.
Energy Density vs. Power Density
The two most common concepts associated with batteries are energy density and power density. Energy density is measured in watt-hours per kilogram (Wh/kg) and is the amount of energy the battery can store with respect to its mass. Power density is measured in watts per kilogram (W/kg) and is the amount of power that can be generated by the battery with respect to its mass. To draw a clearer picture, think of draining a pool. Energy density is similar to the size of the pool, while power density is comparable to draining the pool as quickly as possible.
The Department of Energy’s Vehicle Technologies Office (VTO) works on increasing the energy density of batteries, while reducing the cost, and maintaining an acceptable power density. For more information on VTO’s battery-related projects, please visit the Vehicle Technologies Office website.
Realizing the Potential of Lithium-Ion Battery Technology
The world of facility cleaning operates on tight budgets and tight margins, where even small gains in operational efficiency can drive serious bottom-line savings and significant competitive advantages. Veterans in the industry — from facility managers to building service contractors — are always on the lookout for new tools and technologies that can give them an edge. But they know they can’t afford to take a chance on unproven technology — and they also can’t afford to make big investments that don’t deliver immediate value.
That’s why lithium-ion (Li-ion) battery technology has garnered such widespread interest and intrigue in the facility cleaning industry. Already proven in various applications from automobiles to cell phones, Li-ion batteries have immense potential as a new power source for floor cleaning machines. They provide immediate and significant gains from higher runtime and productivity as well as lower operating costs and a reduction in cost-of-ownership over time.
Many questions and misconceptions still surround this rapidly growing technology. But as more and more cleaning fleets make the switch to Li-ion technology, they’re delivering real-world proof of the comparative advantages — as well as shaping a set of best practices that guide buying decisions toward maximizing the advantages of switching to Li-ion technology.
Expanding Applications for Li-Ion Technology
Experts expect Li-ion technology to continue rapid expansion. The global Li-ion market is expected to grow more than 11% annually over the next five years 1 , led by several key industries:
- Auto manufacturers: Many of the most advanced hybrid vehicles today use Li-ion battery technology. Moreover, these Li-ion-powered vehicles continue to grow in popularity among consumers that value the eco-friendly advantages.
- Golf carts and ATVs: Li-ion batteries are replacing lead-acid batteries in golf carts and off-road vehicle markets. Commercial owners of these vehicles increasingly recognize that switching to Li-ion batteries can reduce labor and maintenance costs while increasing their vehicles’ uptime.
- Public transportation: Municipalities are starting to convert their busses to Li-on power sources — lowering maintenance costs and reducing their environmental impacts.
- Material handling: Industrial and commercial warehousing operations increasingly use forklifts and pallet jacks powered by Li-ion technology. In fact, by 2028, nearly half of all electric fork trucks will be powered by lithium-ion batteries 2 .
- Floor care: Multiple manufacturers of floor care machines now offer scrubbers and sweepers powered by Li-ion technology.
Understanding the Real World Benefits of Li-Ion Technology
Li-ion technology differs at a fundamental level from the traditional battery technologies (i.e., lead-acid) used in floor care equipment — and obviously, is an entirely different category of power source from liquid fuels (propane, diesel or gas). However, for most fleet managers, diving into the technical details of how the Li-ion battery works is less important than understanding how the unique qualities of Li-ion battery technology deliver specific advantages when used in floor care equipment*:
Higher Performance
The high energy density of Li-ion batteries delivers longer machine runtime — increasing runtime by as much as 60%.
Greater Efficiency
Because Li-ion batteries do not require over-charging to mix the electrolyte, they use significantly less electricity during charging — and charge up to 40% faster than lead-acid batteries.
Longer Life
Leading Li-ion batteries deliver a 2000+ charge cycle lifespan, providing additional years of operational use as compared to traditional batteries.
Zero Maintenance
A battery-powered fleet eliminates tedious engine maintenance and fuel storage issues. But Li-ion batteries completely upend traditional battery-management protocol by doing away with battery watering and other battery maintenance. They are also designed to enable opportunity charging. Unlike lead-acid batteries, opportunity charging does not damage or reduce the life of lithium-ion batteries.
Safer
Li-ion batteries ensure operators are not exposed to hazardous battery acid or fumes produced while charging lead-acid batteries. And of course, a Li-ion-powered fleet is emissions-free and eliminates the need to store flammable fuels onsite.
*Statistics based on average Tennant lithium-ion battery offering
The Comparative Advantages of Li-Ion Technology
Li-ion technology differs at a fundamental level from the traditional battery technologies (i.e., lead-acid) used in floor care equipment — and obviously, is an entirely different category of power source from liquid fuels (propane, diesel or gas). However, for most fleet managers, diving into the technical details of how the Li-ion battery works is less important than understanding how the unique qualities of Li-ion battery technology deliver specific advantages when used in floor care equipment*:
Lithium-Ion vs. Liquid Fuel (LPG, Diesel, Gas)
- Uptime: The extended runtime of a Li-ion battery enables full-shift cleaning without requiring operators to stop to fill or change a liquid fuel tank.
- Cost: Li-ion batteries eliminate engine maintenance costs, as well as fuel and fuel storage costs. Operator costs are reduced by eliminating battery watering.
- Safety: Li-ion-powered machines operate at significantly lower dBa sound levels enabling operators to be more aware of their surroundings, and they are emissions-free, improving indoor air quality. Eliminating the storage of flammable liquid fuels onsite delivers safety benefits to all users of the facility.
- Sustainability: Switching to Li-ion batteries eliminates reliance on non-renewable natural resources, while reducing carbon emissions.
Lithium-Ion vs. Lead-Acid Batteries
- Uptime: Li-ion batteries charge up to 40% faster than lead-acid batteries and deliver up to a 60% improvement in machine runtime. Fully-enabled opportunity charging further ensures that machines are always charged and ready to clean.
- Cost: Eliminating battery watering and enabling opportunity charging delivers significant operational cost savings. With a 2000+ charge cycles lifespan, Li-ion batteries reduces replacement cost of multiple batteries.
- Safety: Li-ion batteries eliminate the risk of operators encountering battery acid, and do not produce potentially harmful gases during charging like lead-acid batteries.
- Operator Training: By eliminating all battery maintenance and enabling opportunity charging, Li-ion batteries greatly simplify operator training and reduce the risk of operator misuse and abuse.
*Statistics based on average Tennant lithium-ion battery offering
Emerging Best Practices Guide for Li-Ion Buyers
While the facility cleaning and floor care industries are just beginning to explore the potential of Li-ion technology, there is no shortage of options for would-be buyers. Several manufacturers of floor care equipment now offer machines powered by — or are compatible with — Li-ion technology. In addition, third-party battery vendors offer Li-ion batteries that can be used within compatible machines.
Fortunately, as Li-ion technology begins to gain traction as a high-value power source in the facility cleaning industry, a set of best practices have emerged to guide buyers as they consider multiple vendors and differing approaches.
Choose Fully Integrated Li-Ion Technology
As mentioned, retrofitting existing floor care equipment with third-party Li-ion batteries is an option. However, the shortcomings of choosing a non-integrated, third-party Li-ion battery limit performance gains, can damage equipment and can even create operator safety risks. For example, many third-party Li-ion batteries feature a battery discharge indicator (BDI) on the battery itself (though it should also be noted that some do not feature a BDI at all), where it is not clearly visible to the operator during cleaning. This requires the operator to stop working to check the BDI — or risk being stranded if the battery runs out of power away from a charging area. Moreover, a non-integrated third-party battery should not be expected to communicate with the machine. This could lead to unsafe operating conditions that, again, damage equipment and put operators at risk.
Industry-leading manufacturers design their Li-ion batteries to be fully integrated with their machines where the BMS and cell module work as a single cohesive system. Choosing a fully integrated Li-ion battery solution delivers several benefits:
Maximized Runtime
By designing the Li-ion battery specifically to fit into the machine and properly mate up with the machines unique electrical operating system, fully integrated lithium-ion batteries maximizes runtime
Integrated Battery Management System
A fully integrated battery is an intelligent system where the battery management system (BMS) ensures continuous, real-time communications between the battery and the machine. A fully integrated BMS protects the user and equipment from unsafe operating conditions, automatically shutting off the machine if such conditions are identified.
Simplified Operation
A fully integrated battery enables the operator to turn the machine and battery on and off at the same time with the single machine key switch. Many non-integrated lithium-ion batteries require that the operator turns on the battery before starting the machine. Additionally, a non-integrated battery may have the battery discharge indicator (BDI) on the battery; whereas, an integrated battery allows the operator to constantly see the state of charge through the machine’s BDI. A clearly visible battery discharge indicator ensures that the operator can see real-time battery life without interrupting cleaning.
Warranty and Support
Using third-party batteries in existing cleaning equipment, can void the equipment manufacturer’s warranty. In the event of an issue, the fleet manager may be left bearing the entire cost of repair or replacement. Moreover, a supplier of a fully integrated Li-ion-powered system can deliver more reliable and evidence-based service and support, based on their comprehensive knowledge and experience with every component of the system. Choosing an integrated system with this level of warranty and support helps protect the investment of a lithium-ion power source.
Gaining the Competitive Advantage of a Future-Proof Cleaning Fleet
Though the core objectives of the facility cleaning industry have remained largely the same for decades, veterans know it’s anything but a status-quo business. Small changes can have major impacts on cleaning performance, operational efficiency and the overall health of the business. While major technology changes are few and far between, Li-ion battery technology most certainly represents an innovation that stands to definitively transform the industry. Li-ion technology completely redefines standards for battery and machine performance – delivering significantly longer battery life that drives longer runtime, increased uptime and improved fleet performance. But Li-ion technology benefits more than just the machines – Li-ion batteries dramatically reduce the burdens for both machine operators and fleet managers. A true maintenance-free power source, Li-ion batteries eliminate battery watering and fuel tank filling, while enabling opportunity charging. This frees operators to spend more time cleaning – and frees fleet managers from constant concerns about operator charging behaviors, battery life, fuel costs, battery acid exposure and more.
Industry-leading manufacturers design their Li-ion batteries to be fully integrated with their machines where the BMS and cell module work as a single cohesive system. Choosing a fully integrated Li-ion battery solution delivers several benefits:
For more information or to find out if Li-ion technology may be right for you, contact us.
What’s next for batteries
Expect new battery chemistries for electric vehicles and a manufacturing boost thanks to government funding this year.
January 4, 2023
Every year the world runs more and more on batteries. Electric vehicles passed 10% of global vehicle sales in 2022, and they’re on track to reach 30% by the end of this decade.
Policies around the world are only going to accelerate this growth: recent climate legislation in the US is pumping billions into battery manufacturing and incentives for EV purchases. The European Union, and several states in the US, passed bans on gas-powered vehicles starting in 2035.
The transition will require lots of batteries—and better and cheaper ones.
Most EVs today are powered by lithium-ion batteries, a decades-old technology that’s also used in laptops and cell phones. All those years of development have helped push prices down and improve performance, so today’s EVs are approaching the price of gas-powered cars and can go for hundreds of miles between charges. Lithium-ion batteries are also finding new applications, including electricity storage on the grid that can help balance out intermittent renewable power sources like wind and solar.
But there is still lots of room for improvement. Academic labs and companies alike are hunting for ways to improve the technology—boosting capacity, speeding charging time, and cutting costs. The goal is even cheaper batteries that will provide cheap storage for the grid and allow EVs to travel far greater distances on a charge.
At the same time, concerns about supplies of key battery materials like cobalt and lithium are pushing a search for alternatives to the standard lithium-ion chemistry.
In the midst of the soaring demand for EVs and renewable power and an explosion in battery development, one thing is certain: batteries will play a key role in the transition to renewable energy. Here’s what to expect in 2023.
A radical rethink
Some dramatically different approaches to EV batteries could see progress in 2023, though they will likely take longer to make a commercial impact.
One advance to keep an eye on this year is in so-called solid-state batteries. Lithium-ion batteries and related chemistries use a liquid electrolyte that shuttles charge around; solid-state batteries replace this liquid with ceramics or other solid materials.
This swap unlocks possibilities that pack more energy into a smaller space, potentially improving the range of electric vehicles. Solid-state batteries could also move charge around faster, meaning shorter charging times. And because some solvents used in electrolytes can be flammable, proponents of solid-state batteries say they improve safety by cutting fire risk.
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Novel lithium-metal batteries will drive the switch to electric cars
A new type of battery could finally make electric cars as convenient and cheap as gas ones.
Solid-state batteries can use a wide range of chemistries, but a leading candidate for commercialization uses lithium metal. Quantumscape, for one, is focused on that technology and raised hundreds of millions in funding before going public in 2020. The company has a deal with Volkswagen that could put its batteries in cars by 2025.
But completely reinventing batteries has proved difficult, and lithium-metal batteries have seen concerns about degradation over time, as well as manufacturing challenges. Quantumscape announced in late December it had delivered samples to automotive partners for testing, a significant milestone on the road to getting solid-state batteries into cars. Other solid-state-battery players, like Solid Power, are also working to build and test their batteries. But while they could reach major milestones this year as well, their batteries won’t make it into vehicles on the road in 2023.
Solid-state batteries aren’t the only new technology to watch out for. Sodium-ion batteries also swerve sharply from lithium-ion chemistries common today. These batteries have a design similar to that of lithium-ion batteries, including a liquid electrolyte, but instead of relying on lithium, they use sodium as the main chemical ingredient. Chinese battery giant CATL reportedly plans to begin mass-producing them in 2023.
Sodium-ion batteries may not improve performance, but they could cut costs because they rely on cheaper, more widely available materials than lithium-ion chemistries do. But it’s not clear whether these batteries will be able to meet needs for EV range and charging time, which is why several companies going after the technology, like US-based Natron, are targeting less demanding applications to start, like stationary storage or micromobility devices such as e-bikes and scooters.
Today, the market for batteries aimed at stationary grid storage is small—about one-tenth the size of the market for EV batteries, according to Yayoi Sekine, head of energy storage at energy research firm BloombergNEF. But demand for electricity storage is growing as more renewable power is installed, since major renewable power sources like wind and solar are variable, and batteries can help store energy for when it’s needed.
Lithium-ion batteries aren’t ideal for stationary storage, even though they’re commonly used for it today. While batteries for EVs are getting smaller, lighter, and faster, the primary goal for stationary storage is to cut costs. Size and weight don’t matter as much for grid storage, which means different chemistries will likely win out.
One rising star in stationary storage is iron, and two players could see progress in the coming year. Form Energy is developing an iron-air battery that uses a water-based electrolyte and basically stores energy using reversible rusting. The company recently announced a $760 million manufacturing facility in Weirton, West Virginia, scheduled to begin construction in 2023. Another company, ESS, is building a different type of iron battery that employs similar chemistry; it has begun manufacturing at its headquarters in Wilsonville, Oregon.
Shifts within the standard
Lithium-ion batteries keep getting better and cheaper, but researchers are tweaking the technology further to eke out greater performance and lower costs.
Some of the motivation comes from the price volatility of battery materials, which could drive companies to change chemistries. “It’s a cost game,” Sekine says.
Cathodes are typically one of the most expensive parts of a battery, and a type of cathode called NMC (nickel manganese cobalt) is the dominant variety in EV batteries today. But those three elements, in addition to lithium, are expensive, so cutting some or all of them could help decrease costs.
This year could be a breakout year for one alternative: lithium iron phosphate (LFP), a low-cost cathode material sometimes used for lithium-ion batteries.
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Aggressive new US policies will be put to the test in 2023. They could ultimately fragment the global semiconductor industry.
Recent improvements in LFP chemistry and manufacturing have helped boost the performance of these batteries, and companies are moving to adopt the technology: LFP market share is growing quickly, from about 10% of the global EV market in 2018 to about 40% in 2022. Tesla is already using LFP batteries in some vehicles, and automakers like Ford and Volkswagen announced that they plan to start offering some EV models with the chemistry too.
Though battery research tends to focus on cathode chemistries, anodes are also in line to get a makeover.
Most anodes in lithium-ion batteries today, whatever their cathode makeup, use graphite to hold the lithium ions. But alternatives like silicon could help increase energy density and speed up charging.
Silicon anodes have been the subject of research for years, but historically they haven’t had a long enough lifetime to last in products. Now though, companies are starting to expand production of the materials.
In 2021, startup Sila began producing silicon anodes for batteries in a wearable fitness device. The company was recently awarded a $100 million grant from the Department of Energy to help build a manufacturing facility in Moses Lake, Washington. The factory will serve Sila’s partnership with Mercedes-Benz and is expected to produce materials for EV batteries starting in 2025.
Other startups are working to blend silicon and graphite together for anodes. OneD Battery Sciences, which has partnered with GM, and Sionic Energy could take additional steps toward commercialization this year.
Policies shaping products
The Inflation Reduction Act, which was passed in late 2022, sets aside nearly $370 billion in funding for climate and clean energy, including billions for EV and battery manufacturing. “Everybody’s got their mind on the IRA,” says Yet-Ming Chiang, a materials researcher at MIT and founder of multiple battery companies.
The IRA will provide loans and grants to battery makers in the US, boosting capacity. In addition, EV tax credits in the law incentivize automakers to source battery materials in the US or from its free-trade partners and manufacture batteries in North America. Because of both the IRA’s funding and the EV tax credit restrictions, automakers will continue announcing new manufacturing capacity in the US and finding new ways to source materials.
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Inside a battery recycling facility
Battery materials will soon be short supply. Recycling facilities like one from Redwood Materials could help fill in the gaps.
All that means there will be more and more demand for the key ingredients in lithium-ion batteries, including lithium, cobalt, and nickel. One possible outcome from the IRA incentives is an increase in already growing interest around battery recycling. While there won’t be enough EVs coming off the road anytime soon to meet the demand for some crucial materials, recycling is starting to heat up.
CATL and other Chinese companies have led in battery recycling, but the industry could see significant growth in other major EV markets like North America and Europe this year. Nevada-based Redwood Materials and Li-Cycle, which is headquartered in Toronto, are building facilities and working to separate and purify key battery metals like lithium and nickel to be reused in batteries.
Li-Cycle is set to begin commissioning its main recycling facility in 2023. Redwood Materials has started producing its first product, a copper foil, from its facility outside Reno, Nevada, and recently announced plans to build its second facility beginning this year in Charleston, South Carolina.
With the flood of money from the IRA and other policies around the world fueling demand for EVs and their batteries, 2023 is going to be a year to watch.
This story is a part of MIT Technology Review’s What’s Next series, where we look across industries, trends, and technologies to give you a first look at the future.