How Graphene Can Prevent Overheating

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At the start of autumn, it was reported that Samsung was on the cusp of announcing the world’s first mobile phone with a graphene-based alternative to the traditional lithium-ion batteries. Samsung wasn’t the only company exploring this material. Behind the scenes, each of the major mobile phone retailers are hard at work perfecting graphene components to be used in their products.

Such is the determination to integrate graphene into mobile phones, it’s estimated that by 2021, Samsung and several other mobile phone manufactures will have at least one phone in their range with a graphene battery or graphene components. Apple owns several graphene designs patents, including a foldable smartphone, graphene-based battery system for smartwatches and a heat dissipator to prevent smartphones from overheating.

It would be hard to find a material that’s got the mobile phone industry more excited than graphene. But what exactly is it and how does it stop components from overheating?

What Is Graphene?

Graphene is an allotrope (the property of differing chemical elements that exist in two or more different forms in the same physical state). In layman’s terms, it’s a wonder material that’s super-thin and made of carbon atoms that are layered together in hexagonal shapes.

The material has a unique set of properties that set it apart from other carbon allotropes. Proportionate to its thickness, graphene is about 100 times stronger than the strongest steel, but it has a dramatically smaller density and a surface mass of about 0.763 mg.

Scientists have theorised about graphene for decades. It’s likely been unknowingly produced in small quantities for centuries by pencils and other graphite applications. It was originally observed in electron microscopes in 1962 but only studied whilst supported on metal surfaces.

In 2004, the material was rediscovered, isolated and characterised by physicists, Andre Giem and Konstantin Novoselov whilst working at the University of Manchester. In 2010, both were awarded the Nobel Prize in Physics for their work with Graphene.

Graphene discovered by Andre Giem and Konstantin Novoselov

Revolutionary Potential

Recognising the potential of the material, governments have invested huge sums of money into development. In the US, the Federal government has awarded almost $264 million in graphene-related research grants over the past decade. Recipients have included IBM and the Massachusetts Institute of Technology (MIT).

In the UK, the government has earmarked almost £130 million for graphene programs. This includes over £60 million to the National Graphene Institute, a new centre for graphene engineering and innovation-based at the University of Manchester.

As the world’s strongest material, graphene can be used to enhance the strength of other materials. Tests have proven that adding the material to plastics, metals and other materials can make these materials much stronger – and lighter. Graphene is also the world’s most conductive material to heat. Its properties are ideal for heat-spreading solutions, such as heat sinks. It can also be used to make LED lighting more efficient and have increased longevity.

It may be the world’s thinnest material, but graphene has the highest surface area to volume ratio. This attribute means that it demonstrates great promise when applied to batteries or superconductors. Devices will be able to store more energy and charge quicker – and it can be used to enhance fuel cells.

Moreover, graphene has anti-corrosion coating applications, the ability to make electronics faster and more efficient, initiate faster DNA sequencing – and it will even enhance the efficiency of solar panels.

Graphene and Overheating Components

When your mobile phone gets hot, there are typically three culprits: the battery, the processor, or the screen. Each generates heat which can make your phone seem warm to the touch. Processor transfer at high speeds creates heat as does the light emitting from your phone.

Batteries can also overheat. Lithium-ion batteries can give off significant heat and although safe, there have been circumstances when Samsung phone’s batteries have exploded. However, this problem can be completely negated with graphene batteries.

There have been circumstances when Samsung phone’s batteries have exploded

Graphene researchers have discovered a critical and unexpected relationship between graphene’s chemical structural properties as a host material for electrodes and its ability to surpress the growth of dendrites (filament deposits on the electrodes that can penetrate the barrier between the two halves of the battery) and potentially cause, overheating, electrical shorts and fires.

Given that graphene is just one atom thick, it’s one million times thinner than the diameter of a human hair. In addition to being extremely flexible and an ideal conductor for heat and electricity, it can be placed onto of another material and form a protective shield, stopping overheating and electrical shorts.

In the past, it’s been desirable to dissipate the heat from the system quickly and efficiently, without the need for complex design schemes. For electronics which are approaching the level of 2D, single-to-few-atom-thick stacked layers, heat transfer usually occurs along a conductive plane (2D). This makes heat out-of-plane conductivity is poor which creates a build-up of heat which severely limits high-speed electronics. The hexagonal 3D shape of graphene presents a solution to this problem – something that has remained elusive until very recently.

Moreover, graphene’s excellent electron-transport properties and extremely high carrier mobility, graphene and another direct gap monolayer material, such as transition-metal dichalcogenides (TMDCs) and black phosphorus, are favoured to be used for low-cost, flexible, and highly efficient solar battery devices – and with Apple holding the patent for solar battery charging, it seems as though future iPhones will further integrate the material.

Graphene has the potential to revolutionise a wealth of devices. Such is the application potential of the material; it has also been mooted as a feasible solution for a diverse range of sectors. In the next decade we’re likely to see graphene being integrated into a wealth of different products with improved finesse and confidence being the most likely outcome.

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