Beyond Li-ion Batteries: Could These Alternatives Be the Way to Go?

With a massive focus on electric vehicles and the environment as a whole, new technology and alternatives to current resources are being explored to help meet greener goals.

One central area of interest is the battery industry, especially that of Li-ion technology. 

 

Overview of how a Li-ion battery works. Image used courtesy of EPA and Argonne

 

Although Li-ion battery technology has an indispensable range of applications, it has several limitations, such as high production costs, raw material scarcity, and adverse environmental impact. Researchers are currently developing various alternatives to address these limitations, which this article will aim to explore.

 

Li-ion Battery Technology: Challenges

Since the 1990s, when it became commercially viable, Lithium-ion batteries have remained dominant in the global energy storage scene. 

This domination is primarily due to its wide range of applications in everyday life, such as supplying power in smartphones, cars, electronic devices, grid storage, and even eVTOLs, aka flying cars. It also has one of the highest energy densities, delivering high voltages of up to 3.6 V, suitable for high-power applications, and a low self-discharge rate ranging from 1.5 to 2%. 

Despite those benefits and the wide adaptation and usage, there are a few crucial setbacks:

• Energy Density Limits
• Growing Scarcity of Natural Resources
• High Production Costs
• Safety

As for the issue of energy density, Li-ion batteries may have reached their theoretical energy density limits. Reaching this limit can result in conventional batteries being unable to meet the power requirements in specific applications.

Another major concern is the scarcity of rare-earth metals or rare earth elements (REE), many of which are used in creating EV batteries. Compared to other elements, Lithium is one of those elements that is considered rare. Although it occurs naturally in many types of rocks and some brines, it is usually found in lower concentrations. This concentration limit results in a rising cost since they depend on supply and demand, amongst other factors. Lithium scarcity can also imply higher prices for Li-ion battery production as manufacturers scramble to meet production deadlines. 

A final problem that is often overlooked but could be argued to be the most important is safety. With Li-ion batteries come many safety concerns. A notable one is overheating at higher voltages, which often leads to thermal runaway or explosions. This concern can be so severe that it can trigger a recall of Li-ion battery packs similar to that of 2006.

One way to overcome these challenges is to reinvent and change Li-ion technology as a whole, or to start looking into the next best alternative.

 

Calcium and Hydrogen-based Batteries vs. Li-ion Batteries

Top alternatives and solutions being considered to replace or fix Li-ion technology include calcium and hydrogen-based batteries, plastic Li-ion batteries, and graphene aluminum-ion batteries. 

One promising technology that Tohoku University researchers are currently working on is a new rechargeable battery technology that uses a calcium mono carborane cluster salt (CMC). It uses CMC to develop an electrolyte with remarkable anodic stability, conductivity, and coulombic efficiency. It assures several improvements over Li-ion battery technology.

 

A high-level depiction of calcium and hydrogen-based battery. Image used courtesy of Tohoku University

 

Calcium and hydrogen-based batteries claim have the following benefits over Li-ion batteries:

• Since calcium is amongst the most abundant elements found in the earth’s crust, it is less scarce than Lithium. This availability implies higher sustainability for this technology at a relatively lesser cost.
• Its metal anode has a low reduction potential of about -2.87 V, which is lower than the conventional hydrogen electrode and volumetric capacities of 2072 mAh cm-3, making it as good as Li-ion battery technology.
• The relative cost-effectiveness and higher energy densities make these potential batteries possible substitutes for Li-ion batteries. 

Compared to Li-ion batteries, the calcium and hydrogen-based ones have a significant drawback. They lack suitable electrolytes that offer reductive/oxidative stabilities and high ionic conductivities.

However, the research team employed a fluorine-free electrolyte that uses hydrogen clusters, which promises high conductivity and chemical stability. This solution seems remarkable because it seamlessly handles the high toxicity and recycling complications that often plague Li-ion battery technologies and making it more beneficial. 

A typical drawback to this research is simply that is it research-based. Advancements that start in research typically struggle to move to market or at least might take a few years to do so. One possible alternative that is already in the market space as a Li-ion battery solution is the idea of all polymer batteries.

 

An All Polymer Battery?

An all polymer battery (APB) is a relatively new advancement to the conventional Li-ion battery. Ever since it developed the concept of bipolar structured batteries that use polymer electrolytes in 1998, the APB corporation has made tremendous strides to bring this concept to life. In 2018, the corporation finally commenced moves toward the mass production of APBs.

 

Possibilities of the Novel APB Plastic Battery

The APB plastic battery solves many issues with conventional Li-ion batteries. A few include inefficient design, complicated structure, fire risks, and long and cumbersome manufacturing processes. 

 

Application and technology vs. charge/discharge duration of APBs. Image used courtesy of APB

 

This plastic battery seems to be a potential battery technology shift that resulted from the successful redesigning attempt of the entire Li-ion battery technology. It features a bipolar structure that allows current to flow perpendicularly to its polymer-based current collector. 

Some key improvements the APB technology claims to have over the Li-ion technology include:

• High reliability in abnormal situations
• High flexibility with regards to shape and size
• Innovative manufacturing process
• High energy density
• Polymer-based current collectors that solve overheating issues and reduce fire risks.

Though this innovative battery seems like a possible alternative in the near future, there are still other companies looking into alternatives, especially with graphene. 

 

GMG and UQ’s Collaboration

Graphene Manufacturing Group Ltd. (GMG), in collaboration with the University of Queensland (UQ), is currently developing and testing graphene aluminum-ion batteries. 

They are working together to achieve faster-charging, longer-lasting, and more sustainable batteries that can compete with the conventional Li-ion batteries and possibly replace them. 

Recently-released test results show potential for high-performance graphene aluminum-ion batteries with energy densities from 150 to 160 Wh/kg, a power density of about 7000 W/kg, and an average charging period of 5 minutes. 

Some notable benefits this technology claims to offer includes:

• Longer battery life with zero performance deterioration
• Safer batteries that can minimize overheating issues
• Recyclable and environmentally cells
• Lower production costs and high sustainability 

The technology utilizes graphene, which is becoming a breeding ground for newer innovations. When used as a battery’s component, it could be possible to achieve high capacity, fast charging, lightweight, flexibility, and high-temperature range qualities. It also uses this material as an electrode to power the battery efficiently.

With further improvements on the innovative Li-ion battery alternatives explored in this article, higher-performing, sustainable, and greener energy storage solutions should be closer to reality.

 

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Interested in other recent battery advancements? Find out more in the articles down below.

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