Nanodot

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Nanodot can refer to several technologies which use nanometer-scale localized structures. Nanodots generally exploit properties of quantum dots to localize magnetic or electrical fields at very small scales. Applications for nanodots could include high-density information storage, energy storage, and light-emitting devices.

Contents

Information storage

Magnetic nanodots are being developed for future information storage. [1] Nanodot technology could potentially store over one hundred times more data than today's hard drives. The nanodots can be thought of as tiny magnets which can switch polarity to represent a binary digit. Hard drives typically magnetize areas 200-250 nm long to store individual bits (as of 2006), while nanodots can be 50 nm in diameter or smaller. [1] Thus nanodot-based storage could offer considerably higher information density than existing hard drives. Nanodots could also lead to ultrafast memory. [2]

Battery

In 2014 self-assembled, chemically-synthesized bio-organic peptide nanodots were proposed to reduce charging times in batteries. They are claimed to improve energy density and electrolyte performance. The new battery is said to operate like a (fast-charging) supercapacitor for charging and a (slow-discharge) battery for providing power. [3]

Lithium-ion battery

Applications with nanodot technology have been test in lithium-ion batteries. It has been shown that binder-free three-dimensional (3D) macro-mesoporous electrode architecture yields a high performance supercapacitor-like lithium battery. It is about ten times more efficient compared to the current model of a state-of-the-art graphite anode. This electrode architecture simultaneously allows for rapid ion transfer and ultra-short solid-phase ion diffusion resulting in an efficient new binder-free electrode technique towards the development of high-performance supercapacitor-like Li-ion batteries. [4]

Lithium-sulfur battery

Incorporation of nanodot technology into lithium-sulfur batteries is crucial because rechargeable lithium-sulfur batteries are a significant energy-storage device owing to their eco-friendliness and high theoretical energy density. However, the shuttle effect of soluble polysulfides as well as the slow redox kinetics constrains the development of Li-S batteries. Studies have shown that the coexistence of micropores, mesopores, and macropore in the hierarchical porous carbon are beneficial for physical accommodating/immobilizing active materials sulfur and rapid charge/ion transfer, superior to the most reported biochar-based electrodes, creating an avenue to the design of multifunctional sulfur host for advanced Li-S batteries in the future. [5]

The shuttle effect in lithium-sulfur (Li–S) batteries mainly originates from the diffusion of soluble polysulfides (LiPSs) and their depressed redox kinetics and is responsible for the progressive leakage of active material within the battery itself. Researchers have developed a layer composed of acorn shell porous carbon/Sn4P3 nanodots electrocatalyst which serve as a conductive interface but also provides a dual-adsorption barrier to retain active material and inhibit the LiPSs migrating. [6]

Sodium-ion battery

Sodium-ion batteries are very similar to lithium-ion batteries in that they are both cations. In these cells however, poor cycle stability due to stacking is one of its main challenges but studies have proved that sulfur nanodots are employed as an efficient antiblocking agent of MoS2 sheet. This arrangement of these sulfur sheets exhibit a higher current density with excellent cycling stability, surviving 300 full charge/discharge cycles with a retention of 83.8%. [7]

Sodium-ion batteries also offer an attractive option for potential low cost, large scale energy storage because of the earth's abundance of natural sodium. Red phosphorus is considered as a high capacity anode for sodium-ion batteries. Like silicon in lithium-ion batteries, several limitations, such as large volume expansion upon sodiation/desodiation and low electronic conductance, inhibit the performance of red phosphorus anodes. Scientists have deposited nanodots densely and uniformly onto reduced graphene oxide sheets to minimize the sodium ion diffusion length and the sodiation/desodiation stresses, and creates free space to accommodate the volume variation of phosphorus particles. This results in significant performance improvement for red phosphorus anodes for sodium-ion chemistry and flexible power sources for wearable electronics and smart phone technology. [8]

Potassium-ion battery

Researchers have shown that antimony-based materials with high theoretical capacity have been considered as a promising anode materials for potassium-ion batteries (PIBs). Unfortunately, the large volume expansion leads to rapid capacity fading and poor rate capability. Ultrafine nanodots can shorten the ions diffusion distance with enhanced kinetic process in the battery cell. When applied as the anode for potassium-ion batteries, they all show satisfactory potassium-storage properties in terms of high reversible capacity and superior rate capability, especially the excellent electrochemical performances. [9]

See also

Related Research Articles

Lithium-ion battery Rechargeable battery type

A lithium-ion battery or Li-ion battery is a type of rechargeable battery composed of cells in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge and back when charging. Li-ion cells use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode. Li-ion batteries have a high energy density, no memory effect and low self-discharge. Cells can be manufactured to prioritize either energy or power density. They can however be a safety hazard since they contain flammable electrolytes and if damaged or incorrectly charged can lead to explosions and fires.

Sodium–sulfur battery

A sodium–sulfur battery is a type of molten-salt battery constructed from liquid sodium (Na) and sulfur (S). This type of battery has a high energy density, high efficiency of charge/discharge and long cycle life (>1000), and is fabricated from inexpensive and non-toxic materials. The operating temperatures of 300 to 350 °C and the highly corrosive nature of the sodium polysulfides, primarily make them suitable for stationary energy storage applications. The cell becomes more economical with increasing size. Commercially available cells are typically large with high capacities. This is because larger cells cool down at a slower rate than smaller cells, making it possible to maintain the high operating temperatures.

Molten-salt battery Class of battery that uses molten salts as an electrolyte and offers both a high energy density and a high power density

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 Type of battery

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-ion capacitor Hybrid type of capacitor

A lithium-ion capacitor (LIC) 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.

Lithium–sulfur battery

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.

Nanoball batteries are an experimental type of battery with either the cathode or anode made of nanosized balls that can be composed of various materials such as carbon and lithium iron phosphate. Batteries which use nanotechnology are more capable than regular batteries because of the vastly improved surface area which allows for greater electrical performance, such as fast charging and discharging.

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.

The sodium-ion battery (NIB or SIB) is a type of rechargeable battery analogous to the lithium-ion battery but using sodium ions (Na+) as the charge carriers. Its working principle and cell construction are almost identical with those of commercially widespread lithium-ion battery types, but sodium compounds are used instead of lithium compounds.

Supercapacitor Electrochemical capacitor

A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor with a capacitance value much higher than other capacitors, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries.

A lithium-ion flow battery is a flow battery that uses a form of lightweight lithium as its charge carrier. The flow battery stores energy separately from its system for discharging. The amount of energy it can store is determined by tank size; its power density is determined by the size of the reaction chamber.

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.

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.

Magnesium batteries are batteries that utilize magnesium cations as the active charge transporting agent in solution and as the elemental anode of an electrochemical cell. Both non-rechargeable primary cell and rechargeable secondary cell chemistries have been investigated. Magnesium primary cell batteries have been commercialised and have found use as reserve and general use batteries.

Linda Faye Nazar is a Senior Canada Research Chair in Solid State Materials and Distinguished Research Professor of Chemistry at the University of Waterloo. She develops materials for electrochemical energy storage and conversion. Nazar demonstrated that interwoven composites could be used to improve the energy density of lithium–sulphur batteries. She was awarded the 2019 Chemical Institute of Canada Medal.

Solid-state electrolyte

A solid-state electrolyte (SSE) is a solid ionic conductor and electron-insulating material and it is the characteristic component of the solid-state battery. It is useful for applications in electrical energy storage (EES) in substitution of the liquid electrolytes found in particular in lithium-ion battery. The main advantages are the absolute safety, no issues of leakages of toxic organic solvents, low flammability, non-volatility, mechanical and thermal stability, easy processability, low self-discharge, higher achievable power density and cyclability. This makes possible, for example, the use of a lithium metal anode in a practical device, without the intrinsic limitations of a liquid electrolyte thanks to the property of lithium dendrite suppression in the presence of a solid-state electrolyte membrane. The utilization of a high capacity anode and low reduction potential, like lithium with a specific capacity of 3860 mAh g−1 and a reduction potential of -3.04 V vs SHE, in substitution of the traditional low capacity graphite, which exhibits a theoretical capacity of 372 mAh g−1 in its fully lithiated state of LiC6, is the first step in the realization of a lighter, thinner and cheaper rechargeable battery. Moreover this allows the reach of gravimetric and volumetric energy densities, high enough to achieve 500 miles per single charge in an electric vehicle. Despite the promising advantages, there are still many limitations that are hindering the transition of SSEs from academia research to large-scale production, depending mainly on the poor ionic conductivity compared to that of liquid counterparts. However, many car OEMs (Toyota, BMW, Honda, Hyundai) expect to integrate these systems into viable devices and to commercialize solid-state battery-based electric vehicles by 2025.

The piezoelectrochemical transducer effect (PECT) is a coupling between the electrochemical potential and the mechanical strain in ion-insertion-based electrode materials. It is similar to the piezoelectric effect – with both exhibiting a voltage-strain coupling - although the PECT effect relies on movement of ions within a material microstructure, rather than charge accumulation from the polarization of electric dipole moments.

References

  1. 1 2 Atkins, William (23 Jan 2007). "Nanodots may drastically increase digital data storage capacity". ITWire. Retrieved 4 Apr 2014.
  2. ↑ Johnson, Dexter (20 Apr 2012). "Nanodot Memory Leaves Charge-Storage Memory in the Dust". ITWire. Retrieved 4 Apr 2014.
  3. ↑ "Nanodot-based smartphone battery that recharges in 30 seconds or even less". Gizmag.com. 7 April 2014. Retrieved 2014-04-24.
  4. ↑ Zheng, Xianfeng; Wang, Hongen; Wang, Chao; Deng, Zhao; Chen, Lihua; Li, Yu; Hasan, Tawfique; Su, Bao-Lian (April 2016). "3D interconnected macro-mesoporous electrode with self-assembled NiO nanodots for high-performance supercapacitor-like Li-ion battery". Nano Energy. 22: 269–277. doi:10.1016/j.nanoen.2016.02.017.
  5. ↑ Zhong, Mei-e; Guan, Jindiao; Sun, Jingchun; Guo, Hui; Xiao, Zhubing; Zhou, Nan; Gui, Qingwen; Gong, Daoxin (March 2019). "Carbon nanodot-decorated alveolate N, O, S tridoped hierarchical porous carbon as efficient electrocatalysis of polysulfide conversion for lithium-sulfur batteries". Electrochimica Acta. 299: 600–609. doi:10.1016/j.electacta.2019.01.024.
  6. ↑ Ye, Zhengqing; Jiang, Ying; Feng, Tao; Wang, Ziheng; Li, Li; Wu, Feng; Chen, Renjie (April 2020). "Curbing polysulfide shuttling by synergistic engineering layer composed of supported Sn4P3 nanodots electrocatalyst in lithium-sulfur batteries". Nano Energy. 70: 104532. doi:10.1016/j.nanoen.2020.104532.
  7. ↑ Xu, Zhanwei; Yao, Kai; Li, Zhi; Fu, Licai; Fu, Hao; Li, Jia; Cao, Liyun; Huang, Jianfeng (2018). "Sulfur nanodots as MoS 2 antiblocking agent for stable sodium ion battery anodes". Journal of Materials Chemistry A. 6 (22): 10535–10542. doi:10.1039/C8TA02339E.
  8. ↑ Liu, Yihang; Zhang, Anyi; Shen, Chenfei; Liu, Qingzhou; Cao, Xuan; Ma, Yuqiang; Chen, Liang; Lau, Christian; Chen, Tian-Chi; Wei, Fei; Zhou, Chongwu (27 June 2017). "Red Phosphorus Nanodots on Reduced Graphene Oxide as a Flexible and Ultra-Fast Anode for Sodium-Ion Batteries". ACS Nano. 11 (6): 5530–5537. doi:10.1021/acsnano.7b00557. PMID   28530803.
  9. ↑ Yang, Li; Hong, Wanwan; Tian, Ye; Zou, Guoqiang; Hou, Hongshuai; Sun, Wei; Ji, Xiaobo (April 2020). "Heteroatom-doped carbon inlaid with Sb2X3 (X = S, Se) nanodots for high-performance potassium-ion batteries". Chemical Engineering Journal. 385: 123838. doi:10.1016/j.cej.2019.123838.


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