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Battery basics

Batteries serve as a mobile source of power, allowing electricity-operated devices to work without being directly plugged into an outlet. While many types of batteries exist, the basic concept by which they function remains similar: one or more electrochemical cells convert stored chemical energy into electrical energy. A battery is usually made of a metal or plastic casing, containing a positive terminal (an anode), a negative terminal (a cathode) and electrolytes that allow ions to move between them. A separator (a permeable polymeric membrane) creates a barrier between the anode and cathode to prevent electrical short circuits while also allowing the transport of ionic charge carriers that are needed to close the circuit during the passage of current. Finally, a collector is used to conduct the charge outside the battery, through the connected device.

Eneloop battery design

When the circuit between the two terminals is completed, the battery produces electricity through a series of reactions. The anode experiences an oxidation reaction in which two or more ions from the electrolyte combine with the anode to produce a compound, releasing electrons. At the same time, the cathode goes through a reduction reaction in which the cathode substance, ions and free electrons combine into compounds. Simply put, the anode reaction produces electrons while the reaction in the cathode absorbs them and from that process electricity is produced. The battery will continue to produce electricity until electrodes run out of necessary substance for creation of reactions.

Battery types and characteristics

Batteries are divided into two main types: primary and secondary. Primary batteries (disposable), are used once and rendered useless as the electrode materials in them irreversibly change during charging. Common examples are the zinc-carbon battery as well as the alkaline battery used in toys, flashlights and a multitude of portable devices. Secondary batteries (rechargeable), can be discharged and recharged multiple times as the original composition of the electrodes is able to regain functionality. Examples include lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics.

Batteries come in various shapes and sizes for countless different purposes. Different kinds of batteries display varied advantages and disadvantages. Nickel-Cadmium (NiCd) batteries are relatively low in energy density and are used where long life, high discharge rate and economical price are key. They can be found in video cameras and power tools, among other uses. NiCd batteries contain toxic metals and are environmentally unfriendly. Nickel-Metal hydride batteries have a higher energy density than NiCd ones, but also a shorter cycle-life. Applications include mobile phones and laptops. Lead-Acid batteries are heavy and play an important role in large power applications, where weight is not of the essence but economic price is. They are prevalent in uses like hospital equipment and emergency lighting.

Lithium-Ion (Li-ion) batteries are used where high-energy and minimal weight are important, but the technology is fragile and a protection circuit is required to assure safety. Applications include cell phones and various kinds of computers. Lithium Ion Polymer (Li-ion polymer) batteries are mostly found in mobile phones. They are lightweight and enjoy a slimmer form than that of Li-ion batteries. They are also usually safer and have longer lives. However, they seem to be less prevalent since Li-ion batteries are cheaper to manufacture and have higher energy density.

Graphene and batteries

Graphene, a sheet of carbon atoms bound together in a honeycomb lattice pattern, is hugely recognized as a “wonder material” due to the myriad of astonishing attributes it holds. It is a potent conductor of electrical and thermal energy, extremely lightweight chemically inert, and flexible with a large surface area. It is also considered eco-friendly and sustainable, with unlimited possibilities for numerous applications.

Graphene structure photo

In the field of batteries, conventional battery electrode materials (and prospective ones) are significantly improved when enhanced with graphene. Graphene can make batteries that are light, durable and suitable for high capacity energy storage, as well as shorten charging times. It will extend the battery’s life-time, which is negatively linked to the amount of carbon that is coated on the material or added to electrodes to achieve conductivity, and graphene adds conductivity without requiring the amounts of carbon that are used in conventional batteries.

Graphene can improve such battery attributes as energy density and form in various ways. Li-ion batteries can be enhanced by introducing graphene to the battery’s anode and capitalizing on the material’s conductivity and large surface area traits to achieve morphological optimization and performance.

It has also been discovered that creating hybrid materials can also be useful for achieving battery enhancement. A hybrid of Vanadium Oxide (VO2) and graphene, for example, can be used on Li-ion cathodes and grant quick charge and discharge as well as large charge cycle durability. In this case, VO2 offers high energy capacity but poor electrical conductivity, which can be solved by using graphene as a sort of a structural “backbone” on which to attach VO2 - creating a hybrid material that has both heightened capacity and excellent conductivity.

Another example is LFP ( Lithium Iron Phosphate) batteries, that is a kind of rechargeable Li-ion battery. It has a lower energy density than other Li-ion batteries but a higher power density (an indicator of of the rate at which energy can be supplied by the battery). Enhancing LFP cathodes with graphene allowed the batteries to be lightweight, charge much faster than Li-ion batteries and have a greater capacity than conventional LFP batteries.

In addition to revolutionizing the battery market, combined use of graphene batteries and supercapacitors could yield amazing results, like the noted concept of improving the electric car’s driving range and efficiency.

Batteries and supercapacitors

While there are certain types of batteries that are able to store a large amount of energy, they are very large, heavy and release energy slowly. Capacitors, on the other hand, are able to charge and discharge quickly but hold much less energy than a battery. The use of graphene in this area, though, presents exciting new possibilities for energy storage, with high charge and discharge rates and even economical affordability. Graphene-improved performance thereby blurs the conventional line of distinction between supercapacitors and batteries.

Li-Polymer battery vs Supercapacitor structure

Commercial Graphene-enhanced battery products

In June 2014, US based Vorbeck Materials announced the Vor-Power strap, a lightweight flexible power source that can be attached to any existing bag strap to enable a mobile charging station (via 2 USB and one micro USB ports). the product weighs 450 grams, provides 7,200 mAh and is probably the world’s first graphene-enhanced battery.

Vorbeck Vor-power photo

In May 2014, American company Angstron Materials rolled out several new graphene products. The products, said to become available roughly around the end of 2014, include a line of graphene-enhanced anode materials for Lithium-ion batteries. The battery materials were named “NANO GCA” and are supposed to result in a high capacity anode, capable of supporting hundreds of charge/discharge cycles by combining high capacity silicon with mechanically reinforcing and conductive graphene.

Graphene batteries market report

Developments are also made in the field of graphene batteries for electric vehicles, such as Graphene Nanochem and Sync R&D’s October 2014 plan to co-develop graphene-enhanced Li-ion batteries for electric buses, under the Electric Bus 1 Malaysia program. In August 2014, Tesla suggested the development of a "new battery technology" that will almost double the capacity for their Model S electric car. It is unofficial but reasonable to assume graphene involvement in this battery. UK based Perpetuus Carbon Group and OXIS Energy agreed in June 2014 to co-develop graphene-based electrodes for Lithium-Sulphur batteries, which will offer improved energy density and possibly enable electric cars to drive a much longer distance on a single battery charge.

Another interesting venture, announced in September 2014 by US based Graphene 3D Labs, regards plans to print 3D graphene batteries. These graphene-based batteries can potentially outperform current commercial batteries as well as be tailored to various shapes and sizes.

Other prominent companies which declared intentions to develop and commercialize graphene-enhanced battery products are: Grafoid, SiNode together with AZ Electronic Materials, XG Sciences, Graphene Batteries together with CVD Equipment and CalBattery.

Further reading

Latest Graphene Batteries news

The NGI wil work with Tianjin High-tech Area and Allied Vehicles on graphene-enhanced batteries for EVs

Oct 25, 2016

China's Tianjin High-tech Area (THT) will cooperate with Allied Vehicles Group in Scotland, a leading supplier of adapted and special purpose vehicles and the National Institute of Graphene of the Manchester University on the development of graphene-enhanced batteries for new energy vehicles (NEV).

The Tianjin High-tech Area has formed a complete NEV industrial chain over the years, including battery, motor and other component development. The THT is expecting near-future investments and plans to expand in most parts of the industrial chain.

Grafoid enters agreement to sell its share in Braille Batteries

Oct 19, 2016

Grafoid logoMincom Capital has announced it has entered into a non-binding letter of intent with Grafoid to acquire Grafoid's 75% interest in Braille Holdings which owns Braille Battery. The proposed purchase price is $2 million USD, of which $1 million USD will be paid in cash and $1 million USD will be paid in shares issued to Grafoid from the treasury of Mincom. To fund this acquisition, Mincom plans to raise around $3 million USD.

Grafoid stated that "We see future market opportunities for high performing next generation batteries in the bus and truck manufacturing sectors and we see trends emerging in marine, aviation and medical equipment and other industrial sectors that might benefit from graphene-based energy solutions".

Graphene for the Display and Lighting Industries

Fisker's new electric vehicle will have a graphene-based battery

Oct 05, 2016

Henrik Fisker, owner of failed automotive venture "Fisker Automotive", said recently that he plans to launch a new electric car company next year to compete with Tesla. According to Fisker, the new electric cars will be powered by a long-range battery that uses graphene to extend its range and life and reduce charging time. The company is targeting a 400-mile driving range between charges.

It was not revealed who is funding this new California-based venture, called Fisker Inc, and a new battery subsidiary, Fisker Nanotech. In an interview, Fisker said his new company plans a battery-powered model aimed at the Tesla Model S, which is priced at about $65,000. He did not specify when production would begin. A second smaller Fisker electric car will follow, Fisker said, and will target the upcoming Tesla Model 3, which is expected to start at about $35,000.

Talga Resources announces that its phase 2 graphene plant commissioning is complete

Sep 28, 2016

Talga Resources logoTalga Resources has announced that commissioning of all stages of the Phase 2 German pilot test facility has been successfully completed.

In April 2016, Talga announced the commissioning of its Phase 2 processing plant in Germany and has now provided further updates. The pilot test plant is currently configured so that approximately 76% of the input graphitic carbon reports to graphene products (FLG and GNP) and the remaining carbon reports to Talga’s building sector (micrographite) products.

Lomiko to present graphene supercapacitor prototype at Battery Materials Conference in Toronto

Sep 22, 2016

Lomiko Metals has announced that it will be presenting a summary of the Graphene Energy Storage Devices Corp. (GESD) Graphene Supercapacitor Project at the Battery Material Conference in Toronto September 2016.

Graphene ESD supercapacitor prototype image

GESD is currently working on scale-up of the technology and an in-field evaluation of the energy storage unit with Stony Brook University. The GESD-SBU team demonstrated design and implementation of a sealed high-voltage EDLCs energy storage unit. The unit is internally balanced, there is no need for an external circuit. The electrode is very cost-effective nano-carbon composite either of a commercial carbon or of graphene platelets with carbon nanotubes. The nano-carbon electrode materials were used for deposition and assembly of a working prototype of an internally balanced high-voltage energy storage unit. The bench-top prototype unit, tested up to 10 V, exhibited good discharge characteristics and charge retention. This development enables new compact energy storage solutions for grid and vehicular applications.