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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

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.

Graphene for the Display and Lighting Industries

Talga Resources to collaborate with German JennaBatteries on graphene-enhanced flow batteries

Sep 18, 2016

Talga Resources logoTalga Resources recently signed a collaboration agreement with JenaBatteries to jointly explore the use of Talga’s graphene products in flow batteries. Under the Agreement, Talga will formulate and supply graphene for testing in components producing JenaBatteries’ patented polymer flow battery, a type of redox flow battery suitable for commercial scale and grid applications.

Talga’s graphene will aim to reduce manufacturing costs and increase the performance and longevity of the flow battery components by utilizing graphene’s properties of conductivity, chemical inertness and impermeability.

German team develops technique to produce defect-free graphene

Sep 07, 2016

Researchers at the German FAU have created defect-free graphene directly from graphite. Using the additive benzonitrile, the team designed a technique to produce defect-free graphene directly from a solution that enables selective electronic properties to be set through the various charge carriers and enables the production of efficient and cost-effective graphene.

technique to make defect-free graphene by FAU imageThe solution benzonitrile (grey circle) removes the causes of possible defects and turns red, resulting in defect-free graphene (red circle).

With the addition of a solvent called benzonitrile, defect-free graphene can be obtained without the formation of any additional functional groups. In addition, the benzonitrile molecule formed as a byproduct of the reaction remains red unless it comes into contact with water or oxygen. This color change helps to easily determine the number of charge carriers in the system with the help of absorption measurements. This could give battery and graphene researchers a new way to determine the charge state, as previously could only be done by measuring voltage.

New 3D printed graphene supercapacitors by Swinburne researchers

Jul 31, 2016

Scientists from Swinburne University in Australia have reportedly developed a new supercapacitor made from 3D printed graphene which can hold a larger charge of energy, is recharged in a matter of seconds and will last a very long time.

The supercapacitor is said to be extremely efficient, as it charges in a matter of seconds and holds a larger charge because it consists of multiple sheets of graphene – creating a very large surface area to store energy on. What’s more, charging and discharging won’t degrade the battery’s quality, so they can last a very long time. These remarkable supercapacitors were first presented at Fresh Science Victoria 2016 earlier this year.