A nanowire battery uses nanowires to increase the surface area of one or both of its electrodes, which improves the capacity of the battery. Some designs (silicon, germanium and transition metal oxides), variations of the lithium-ion battery have been announced, although none are commercially available. All of the concepts replace the traditional graphite anode and could improve battery performance. Each type of nanowire battery has specific advantages and disadvantages, but a challenge common to all of them is their fragility. [1]
Silicon is an attractive material for applications as lithium battery anodes because of its discharge potential and high theoretical charge capacity (ten times higher than that of typical graphite anodes currently used in industry). Nanowires could improve these properties by increasing the amount of available surface area in contact with the electrolyte, increasing the anode’s power density and allowing for faster charging and discharging. However, silicon swells by up to 400% as it alloys with lithium during charging, causing it to break down. This volume expansion occurs anisotropically, caused by crack propagation immediately following a moving lithiation front. These cracks result in pulverization and substantial capacity loss noticeable within the first few cycles. [2]
Nanowires may help mitigate the volume expansion. The small nanowire diameter allows for improved accommodation of volume changes during lithiation. Another advantage is that, because all nanowire are attached to the current collector, they can serve as direct pathways for charge transport. By contrast, in particle-based electrodes, charges are forced to move from particle to particle, a less efficient process. Silicon nanowires have a theoretical capacity of roughly 4,200 mAh g−1, larger than that of other forms of silicon and much larger than that of graphite (372 mAh g−1). [3]
Like graphite anodes, silicon anodes form passivation layers (solid-electrolyte interphases) on their surfaces during the first charge cycle. Coating silicon nanowires with carbon can improve the stability of these layers. [4]
Doping impurities, such as phorphorus or boron, into the nanowire anode can also improve performance by increasing the conductivity. [5]
An anode using germanium nanowire was claimed to have the ability to increase the energy density and cycle durability of lithium-ion batteries. Like silicon, germanium has a high theoretical capacity (1600 mAh g-1), expands during charging, and disintegrates after a small number of cycles. [6] [7] However, germanium is 400 times more effective at intercalating lithium than silicon, making it an attractive anode material. The anodes claimed to retain capacities of 900 mAh/g after 1100 cycles, even at discharge rates of 20–100C. This performance was attributed to a restructuring of the nanowires that occurs within the first 100 cycles to form a mechanically robust, continuously porous network. Once formed, the restructured anode loses only 0.01% of capacity per cycle thereafter. [8] The material forms a stable structure after these initial cycles that is capable of withstanding pulverization. In 2014, researchers developed a simple way to produce nanowires of germanium from an aqueous solution. [9]
Transition metal oxides (TMO), such as Cr2O3, Fe2O3, MnO2, Co3O4 and PbO2, have many advantages as anode materials over conventional cell materials for lithium-ion battery (LIB) and other battery systems. [10] [11] [12] Some of them possess high theoretical energy capacity, and are naturally abundant, non-toxic and also environmentally friendly. As the concept of the nanostructured battery electrode has been introduced, experimentalists start to look into the possibility of TMO-based nanowires as electrode materials. Some recent investigations into this concept are discussed in the following subsection.
Lead-acid battery is the oldest type of rechargeable battery cell. Even though the raw material (PbO2) for the cell production is fairly accessible and cheap, lead-acid battery cells have relatively small specific energy. [13] The paste thickening effect (volumetric expansion effect) during the operation cycle also blocks the effective flow of the electrolyte. These problems limited the potential of the cell to accomplish some energy-intensive tasks.
In 2014, experimentalist successfully obtained PbO2 nanowire through simple template electrodeposition. The performance of this nanowire as anode for lead-acid battery has also been evaluated. Due to largely increased surface area, this cell was able to deliver an almost constant capacity of about 190 mAh g−1 even after 1,000 cycles. [14] [15] This result showed this nanostructured PbO2 as a fairly promising substitute for the normal lead-acid anode.
MnO2 has always been a good candidate for electrode materials due to its high energy capacity, non-toxicity and cost effectiveness. However, lithium-ion insertion into the crystal matrix during charging/discharging cycle would cause significant volumetric expansion. To counteract this effect during operation cycle, scientists recently proposed the idea of producing a Li-enriched MnO2 nanowire with a nominal stoichiometry of Li2MnO3 as anode materials for LIB. This new proposed anode materials enable the battery cell to reach an energy capacity of 1279 mAh g−1 at current density of 500 mA even after 500 cycles. [16] This performance is much higher than that of pure MnO2 anode or MnO2 nanowire anode cells.
Heterojunction of different transition metal oxides would sometimes provide the potential of a more well-rounded performance of LIBs.
In 2013, researchers successfully synthesized a branched Co3O4/Fe2O3 nanowire heterostructure using hydrothermal method. This heterojunction can be used as an alternative anode for the LIB cell. At operation, Co3O4 promotes a more efficient ionic transport, while Fe2O3 enhances the theoretical capacity of the cell by increasing the surface area. A high reversible capacity of 980 mAh g−1 was reported. [17]
The possibility of fabrication heterogeneous ZnCo2O4/NiO nanowire arrays anode has also been explored in some studies. [18] However, the efficiency of this material as anode is still to be evaluated.
In 2016, researchers at the University of California, Irvine announced the invention of a nanowire material capable of over 200,000 charge cycles without any breakage of the nanowires. The technology could lead to batteries that never need to be replaced in most applications. The gold nanowires are strengthened by a manganese dioxide shell encased in an Plexiglas-like gel electrolyte. The combination is reliable and resistant to failure. After cycling a test electrode about 200,000 times, no loss of capacity or power, nor fracturing of any nanowires occurred. [19]
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit. Electrodes are essential parts of batteries that can consist of a variety of materials depending on the type of battery.
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. In comparison with other rechargeable batteries, Li-ion batteries are characterized by a higher specific energy, higher energy density, higher energy efficiency, longer cycle life and longer calendar life. The invention and commercialization of Li-ion batteries is considered as having one of the largest societal impacts in human history among all technologies, as was recognized by 2019 Nobel Prize in Chemistry. More specifically, Li-ion batteries enabled portable consumer electronics, laptop computers, cellular phones and electric cars, or what has been called e-mobility revolution. It also sees significant use for grid-scale energy storage, as well as military and aerospace applications.
Molten-salt batteries are a class of battery that uses molten salts as an electrolyte and offers both a high energy density and a high power density. Traditional non-rechargeable thermal batteries can be stored in their solid state at room temperature for long periods of time before being activated by heating. Rechargeable liquid-metal batteries are used for industrial power backup, special electric vehicles and for grid energy storage, to balance out intermittent renewable power sources such as solar panels and wind turbines.
Nanobatteries are fabricated batteries employing technology at the nanoscale, particles that measure less than 100 nanometers or 10−7 meters. These batteries may be nano in size or may use nanotechnology in a macro scale battery. Nanoscale batteries can be combined to function as a macrobattery such as within a nanopore battery.
Lithium iron phosphate or lithium ferro-phosphate (LFP) is an inorganic compound with the formula LiFePO
4. It is a gray, red-grey, brown or black solid that is insoluble in water. The material has attracted attention as a component of lithium iron phosphate batteries, a type of Li-ion battery. This battery chemistry is targeted for use in power tools, electric vehicles, solar energy installations and more recently large grid-scale energy storage.
A lithium-ion capacitor is a hybrid type of capacitor classified as a type of supercapacitor. It is called a hybrid because the anode is the same as those used in lithium-ion batteries and the cathode is the same as those used in supercapacitors. Activated carbon is typically used as the cathode. The anode of the LIC consists of carbon material which is often pre-doped with lithium ions. This pre-doping process lowers the potential of the anode and allows a relatively high output voltage compared to other supercapacitors.
The lithium–sulfur battery is a type of rechargeable battery. It is notable for its high specific energy. The low atomic weight of lithium and moderate atomic weight of sulfur means that Li–S batteries are relatively light. They were used on the longest and highest-altitude unmanned solar-powered aeroplane flight by Zephyr 6 in August 2008.
A solid-state battery uses solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries.
Nanoarchitectures for lithium-ion batteries are attempts to employ nanotechnology to improve the design of lithium-ion batteries. Research in lithium-ion batteries focuses on improving energy density, power density, safety, durability and cost.
The lithium–air battery (Li–air) is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.
A metal–air electrochemical cell is an electrochemical cell that uses an anode made from pure metal and an external cathode of ambient air, typically with an aqueous or aprotic electrolyte.
A potassium-ion battery or K-ion battery is a type of battery and analogue to lithium-ion batteries, using potassium ions for charge transfer instead of lithium ions. It was invented by the Iranian/American chemist Ali Eftekhari in 2004.
Sodium-ion batteries (NIBs or SIBs) are several types of rechargeable batteries, which use sodium ions (Na+) as its charge carriers. In some cases, its working principle and cell construction are similar to those of lithium-ion battery (LIB) types, but it replaces lithium with sodium as the cathode material, which belongs to the same group in the periodic table as lithium and thus has similar chemical properties. In other cases, aqueous Na-ion batteries are quite different from Li-ion batteries.
Aluminium-ion batteries are a class of rechargeable battery in which aluminium ions serve as charge carriers. Aluminium can exchange three electrons per ion. This means that insertion of one Al3+ is equivalent to three Li+ ions. Thus, since the ionic radii of Al3+ (0.54 Å) and Li+ (0.76 Å) are similar, significantly higher numbers of electrons and Al3+ ions can be accepted by cathodes with little damage. Al has 50 times (23.5 megawatt-hours m-3) the energy density of Li and is even higher than coal.
Research in lithium-ion batteries has produced many proposed refinements of lithium-ion batteries. Areas of research interest have focused on improving energy density, safety, rate capability, cycle durability, flexibility, and cost.
NASICON is an acronym for sodium (Na) Super Ionic CONductor, which usually refers to a family of solids with the chemical formula Na1+xZr2SixP3−xO12, 0 < x < 3. In a broader sense, it is also used for similar compounds where Na, Zr and/or Si are replaced by isovalent elements. NASICON compounds have high ionic conductivities, on the order of 10−3 S/cm, which rival those of liquid electrolytes. They are caused by hopping of Na ions among interstitial sites of the NASICON crystal lattice.
Lithium–silicon battery is a name used for a subclass of lithium-ion battery technology that employs a silicon-based anode and lithium ions as the charge carriers. Silicon based materials generally have a much larger specific capacity, for example 3600 mAh/g for pristine silicon, relative to graphite, which is limited to a maximum theoretical capacity of 372 mAh/g for the fully lithiated state LiC6. Silicon's large volume change (approximately 400% based on crystallographic densities) when lithium is inserted is one of the main obstacles along with high reactivity in the charged state to commercializing this type of anode. Commercial battery anodes may have small amounts of silicon, boosting their performance slightly. The amounts are closely held trade secrets, limited as of 2018 to at most 10% of the anode. Lithium-silicon batteries also include cell configurations where Si is in compounds that may at low voltage store lithium by a displacement reaction, including silicon oxycarbide, silicon monoxide or silicon nitride.
Lithium nickel manganese cobalt oxides (abbreviated NMC, Li-NMC, LNMC, or NCM) are mixed metal oxides of lithium, nickel, manganese and cobalt with the general formula LiNixMnyCo1-x-yO2. These materials are commonly used in lithium-ion batteries for mobile devices and electric vehicles, acting as the positively charged cathode.
A solid-state silicon battery or silicon-anode all-solid-state battery is a type of rechargeable lithium-ion battery consisting of a solid electrolyte, solid cathode, and silicon-based solid anode.
This is a history of the lithium-ion battery.