Transparent battery.

Since the end of February 2013, the team from the Japanese Kogakuin University – six men, led by Professor Sato, have been engaged in the development and implementation of innovative idea – almost transparent lithium-ion battery.

Finally, after two and a half years, namely 27 August 2015, on held in Tokyo exhibition «Innovation Japan 2015», researchers presented to the public a working prototype, translucent battery that can be charging by the light of different wavelengths, from red to near ultraviolet.

Thin films of electrodes of anode and cathode, the thickness of 90 and 80 nanometers respectively, have turned out almost transparent. The larger the charging light wavelength, the more transparent electrodes-films after charging. Thus, under the effect of green light, whose wavelength is 550 nanometers, general transparency is 60%, and under the action of sunlight, the density of the electrodes of lithium is significantly increased, and the transparency is decreased to 30%.

The basis of electrolyte for the positive electrode, it has been decided to use Li3Fe2 (PO4) 3 (LFP), and for negative – Li4Ti5O12 (LTO) and LiPF6 (hexafluorophosphate of lithium). In the production of conventional, non-transparent lithium-ion batteries also are widely used these materials.

In 2013, the researchers chose their as the most suitable for this goal. The films of anode and cathode were applied on glass substrates at an air temperature of 550 degrees for 30 and 10 minutes, respectively.

These batteries can be charged both by sunlight, replacing the solar panels, and by other light sources of appropriate brightness. The demonstration at the exhibition showed how the new battery five times was charged and discharged from the ultraviolet with the energy density of 10 mW / cm², which is about 10% of normal sunlight. The output voltage was 3.6 volts, as in conventional lithium batteries.

Tests in the laboratory prior to exhibition showed that 20 cycles of charge-discharge, a new type of battery can withstand without loss in the characteristics.

Inventors believe that their transparent batteries will be fully perspective solution to cover the windows of buildings, car glasses and other transparent surfaces as a light toning, capable of producing an electric current.

This is exactly that will allow to unite renewable energy sources, methods of accumulation and storage of this energy, with the latest systems of so-called “smart buildings”, the windows of which will collect and store solar energy.

Aluminum batteries.

Almost thirty years of searching for ways to improve the aluminum-ion battery are nearing to its end. The first battery with aluminum anode, inexpensive and durable, was developed by scientists from Stanford University.

Researchers say, that their child may well be a safe alternative to lithium-ion batteries which are everywhere used today, as well as alkaline batteries, which are environmentally harmful.

Do not be amiss to recall that the lithium-ion batteries are sometimes ignited. Chemistry professor Dai Hongzhi is confident that his new battery does not burn, even if to drill it. Colleagues of Professor Dai described new batteries as a “super-fast rechargeable aluminum-ion batteries.”

Because of low cost, fire safety, and the ability to create a large electrical capacitance, aluminum has long attracted the attention of researchers, but many years have gone for creating of commercially viable aluminum-ion battery, which could produce enough power even after many charge-discharge cycles.

The scientists had overcome many obstacles, including: the disintegration of the cathode material, a low voltage of cell discharge (about 0.55 volts), the loss of capacity and lack of life-cycle (less than 100 cycles), rapid loss of power (from 26 to 85 per cent after 100 cycles).

Now scientists presented the battery on basis of aluminum with high stability, in which they used an aluminum metal anode with a cathode made of three-dimensional graphite foam. Before this time, has been tried many different materials for the cathode, and the decision in favor of the graphite was found quite by accident.

In their experimental samples, Stanford University team placed an aluminum anode, graphite cathode, and secure liquid ionic electrolyte consisting mainly of salt solutions into a flexible polymeric package.

An important advantage of the new batteries is their ultra-fast charging. Typically, lithium-ion batteries in smartphones are recharged for several hours, while the prototype of new technology demonstrates an unprecedented rate of charging up to one minute.

The durability of the new batteries is particularly striking. Battery life is more than 7500 charge-discharge cycles, and without loss of power. The authors report that this is the first model of aluminum-ion batteries, with ultra- fast charging. A typical lithium-ion battery can withstand only 1,000 cycles.

A notable feature of the aluminum battery is its flexibility. The battery can be bent, that indicate the potential for its use in the flexible gadgets. In addition, aluminum is much cheaper than lithium.

An aluminum-ion battery generates a voltage about 2 volts. This is the highest indicator that someone has made with aluminum, and in future this figure will be improved, say the developers of new batteries.

Saline batteries.

The most popular are alkaline and saline batteries. Saline elements (Le Klanshe) use:

  • as an electrolyte – ammonium chloride;
  • as cathode – zinc;
  • anode is manganese dioxide.

Among the disadvantages of saline batteries are:

  • A sharp voltage drop during discharge;
  • A significant reduction of capacity at increasing discharge currents to the values necessary for modern devices;
  • A sharp deterioration of productivity at low temperatures;
  • A small storage period (about two years).

The term “nominal capacity” is rarely used for characteristic of saline batteries, because their capacity highly depends on the mode and conditions of use.

The final discharge voltage is set according to the load in the range of 0.7-1.0 V.
All this determines the service life of the saline batteries, which is less than 1.5-3 years.

The advantage of these elements is only a low cost.
The chloride or zinc- chloride batteries are often also referred to the class of saline batteries. The main difference is in zinc chloride which is added to the electrolyte.

These batteries have several more voltage – 1.6 volts.
When using ammonium chloride, electrode processes are described in the following equation:

2MnO2 + 2NH4Cl + Zn → ZnCl2 · 2NH3 + H2O + Mn2O3

When using zinc-chloride:

8MnO2 + 4Zn + 2ZnCl2 + 9H2O → 8MnOOH + ZnCl2 · 4ZnO · 5H2O

Energy indicators of elements with zinc-chloride electrolyte are much higher: at medium and high load currents, they can provide 1.5-2 times the duration of the work. The efficiency at low temperatures also is higher.

Design of saline batteries.

The body of saline elements made of zinc is a negative electrode. The positive electrode is a briquette of compressed active mass, moistened by electrolyte, in the center of which is located the carbon rod impregnated with paraffin-based formulations to reduce water loss from the electrolyte. The saline elements have a gas chamber, which receives the gases emitted during the discharge and self-discharge. To reduce the likelihood of leaks due to pitting corrosion of the zinc thin-walled glass, cell is placed in a sheath made of cardboard or polymer, sometimes additionally is used sheath made of tinplate. In this case, the bottom and the top part of the battery also is covered by tinplate.

Applications of batteries.

The battery can be designed for: heavy loads (current 0.2 A), normal loads (current 0.1A) and low loads (current 0,01A). Most manufacturers indicate the types of devices for which battery is best suited, on the package. But this does not always happen. If the type of device not specified on the package, the following information will help to make the right choice of battery for your device.

Saline batteries are fundamentally unsuitable for installation in devices with high load (for example, in digital cameras with flash) and are unsuitable for devices with normal loads (for example, flashlight, CD-player, and some children’s toys).

They have a small capacity (600-800 mAh) and are designed for use in devices with low and minimal power consumption, such as: remote control, electronic thermometer, tester, kitchen scales, table or wall clocks, etc. They are not designed for heavy loads, so they should not be inserted into the devices containing the electric motor (toys, CD-players), flashlights, cameras! In the toy or flashlight they can work only 20-30 minutes.

Alkaline batteries can be insert, anywhere – in devices with low, normal or high loads – they will provide a good result.

Alkaline batteries have a relatively large capacity (1500-3200 mAh) and are optimal for use in devices with moderate and high energy consumption: digital cameras with flash, flashlights, CD-players, toys, office phones, etc. Alkaline batteries with label “photo” have an increased capacity and are designed for use in cameras. Such products are more expensive, but they have a longer life. Photo-batteries can faster give energy, which positively affects the speed of the device.

In the devices with low power consumption, such as a remote control, they show excellent results and serve for several years.

Lifetime of saline and alkaline batteries depends on the discharge current: the higher discharge current, the less service life.

Regarding mercury batteries, twenty or thirty years ago they were widely used as a power source for electronic watches, pacemakers, hearing aids, photographic exposure meters, in the military devices (night-vision devices, radio beacons, etc.), in aviation and space vehicles.

Today, spread of mercury batteries is limited. In most countries, the production and use of such batteries are prohibited due to the toxicity of mercury and the problem of safe disposal.

Silver batteries as a power source for consumer electronic devices today do not find mass distribution because of the high cost of silver. Only small-sized and miniature batteries are in demand, in the manufacture of which uses a small amount of silver, for example, batteries for watches, motherboards, computers and laptops, calculators, hearing aids, musical greeting cards, key fobs, wherever use of battery of a larger size is impossible.

Lithium batteries with high currents can serve longer than the best Alkaline batteries, therefore are used in most devices with high power consumption. They are widely used in computer equipment, medical equipment, some toys, and so on. Also, they are widely used in the military industry, aviation, navy.

Fuel cells.

Fuel cells are chemical power sources. They carry out direct conversion of fuel energy into electricity. It is an electrochemical device as a result of highly effective “cold” combustion of the fuel itself generates electricity.

What is burning in a fuel cell?

Fossil fuels (coal, gas and oil) basically consists of carbon. The combustion of fuel atoms lose their electrons, and oxygen atoms acquire them. Because during the oxidation, the carbon and oxygen atoms are connected in combustion products – carbon dioxide molecule. This process takes place energetically: atoms and molecules of substances involved in burning, acquire great speed, and this leads to an increase in its temperature. They begin to emit light – the flame appears.
The chemical reaction of carbon combustion is as follows:

C + O2 = CO2 + heat

In the process of burning chemical energy is converted into heat energy through the exchange of electrons between atoms of fuel and oxidant. This exchange takes place chaotically.
Burning – electron exchange between atoms, and electricity – directional movement of electrons.

Fuel cell comprises an anode, a cathode and an electrolyte. At the anode is oxidized, i.e. loses electrons, the reducing agent (fuel CO or H2), the free electrons are coming from the anode to an external circuit, and positive ions are confined at the anode-electrolyte (CO +, H +). On the other end of the chain, the electrons approach the cathode, on which is the reduction reaction (electron attachment oxidant O2-). Then, the oxidant ions are transferred by electrolyte to the cathode.

In the fuel cell are brought together three phases of physicochemical system:

  • gas (fuel and oxidant);
  • electrolyte (conductor of ions);
  • metal electrode (conductor of electrons).

In the fuel cell occurs the energy conversion of redox reaction into electrical energy, and, oxidation and reduction processes are spatially separated by an electrolyte. The electrodes and electrolyte are not involved in the reaction, but in real designs eventually are contaminated with fuel impurities. Electrochemical combustion can take place at low temperatures and virtually lossless.

Complicates the use of fuel cells that fact that the fuel for them is necessary to “prepare”. For fuel cells, hydrogen is produced by converting the organic fuel or coal gasification.

How to extend battery life in a mobile phone?

The widespread use of mobile technology in recent years has caused the development of autonomous power sources. Mobile phones multiply their functions, which need electric power, so they require more compact and at the same time more capacious batteries. If earlier battery charge was enough for 3-5 days, now it is fulfilled 2-3 cycles per day. So you need to think how to prolong battery life.

Here is a list of methods that really help to prolong the life of the battery:

1. Before the first use, fully charge the battery.

2. The battery should never be fully discharged. Modern lithium-ion batteries are working on a completely different principle. For maximum impact from them you need to make sure that the charge does not fall below 50%. Statistics in this matter shows: when the battery is charging from the zero power – it withstands 400-600 cycles, with 10-20% – 1000-1100 cycles.

3. Use your mobile phone for its intended purpose. Battery life will be reduced by several times, if you will play games and if Wi-Fi, GPS are enabled for a long time.

4. High temperature is one of the most harmful factors for lithium-ion batteries. Even in idle state they suffer from heat exposure. At zero temperature, the battery will lose 6% of capacity per year at +25 – 20% at +40 degrees – 35%. Therefore, you need adhere to at least the elementary rules of phone storage, for example, do not leave it exposed to direct sunlight or on hot objects.

5. Do not use the cordless charging. This method of energy recovery at first sight seems ideal. However, cordless chargers can overheat the battery, which greatly reduces its life.

6. When stored charge must always remain at a level of 30-50%. If a fully discharged battery will be idle for a long time, in the future it may not come back to life.

7. Use only original chargers for mobile phones. The analogs can exceed or lower the regulatory voltages. In the first case this leads to a reduction of battery life in 2 times, in the second – the battery capacity is reduced to 10%. Devices, controlling the charge level are in the phone, and are intended only for use with native batteries.

Under normal operating conditions, the service life of lithium-ion battery is 3-5 years. That will be enough, because many people tend to often buy new smartphones. You just need to follow all these rules, and the battery will be able to work out the time allotted to it.

How to choose a battery?

Nowadays, the battery is one of the most common sources of power for small appliances and electronics. Batteries are used in a huge number in electronic devices: hours, flashlight, toys, camera, remote control, computer mouse, and many other places, and almost everyone from time to time faced with the need for the acquisition and replacement. But not every one of us, buying a new battery, makes this consciously, that is with the knowledge of what kind of battery, in this case fit better and will serve longer.

Most often in uninformed person in choosing the battery the following problems occur: the battery for some reason, works too short time, while it was expected that it will work for much longer, it not “holds” the voltage, leaks and spoils the equipment. Perhaps battery “is dead” because your choice was wrong.

So, how to choose the right battery?

If you decide to buy a battery – do the following:

1. Choose batteries consciously remember that they are included in the list of goods that are not subject to return and an exchange.

2. Buy only the batteries that are designed for your device and are able to withstand the load.

3. When buying a battery check its expiration date. It is better to buy batteries from the production date of which has not come a year. Do not buy batteries, storage period has come to an end. In this case, its capacity may be lower than capacity of similar newer batteries.

4. Do not buy batteries (especially salt water batteries) during the cold season in the open air and in unheated night stalls. At low temperatures the capacity of alkaline batteries slightly falls.

5. Batteries of known companies sometimes are counterfeited, so buying a battery, before purchasing you should to inspect it carefully. Pay attention to the quality of printing on the packaging and on the battery, the text should be printed clearly, and the words should be written correctly.

Remember, battery is a small product, but it can be dangerous.

To avoid possible damage to health, observe the precautions: do not disassemble the battery, do not throw it into the fire.

Disposal of the batteries.

It is estimated that one battery, carelessly thrown in the trash, may contaminate by the heavy metals of about 20 square meters of land, and in the forest area is the territory habitat of two trees, two moles, a hedgehog and several thousand of earthworms!
The batteries contain a variety of metals – mercury, nickel, cadmium, lead, lithium, manganese, and zinc, which tend to accumulate in living organisms, including the human body and cause significant harm to health.

Rules of storage and disposal of batteries:

Choose the correct battery type and size, in accordance with the recommendations of the device manufacturer, in which will be used batteries.
For a high productivity battery, the battery compartment and the surface of the contacts you should keep clean by wiping them with a clean eraser or cloth when replacing the batteries.
If you do not intend to use the device for several months, it is better to pull out the batteries.
Remove the batteries from the device connected to the household power outlet (AC).
Follow the polarity when inserting the batteries (the location of the terminals + (plus) and – (minus)). WARNING: Some devices operating on 3 or more batteries, can work, even if one battery is inserted incorrectly.
Store batteries in a dry place at room temperature. Do not refrigerate the batteries; it will shorten their service life.

Operation in extreme temperatures also reduces endurance of the batteries. Try not to leave appliances running on batteries, in the heat.
Some batteries with expired shelf life under the influence of high temperatures start to leak.

Alkaline batteries of general-purpose must be disposed of as follows:

Alkaline batteries can be disposed of with normal household waste. It is perfectly safe!

However, in areas where is provided the program for disposing of used electrical appliances, we strongly recommend to dispose of used batteries and rechargeable batteries at special collection points installed in retail stores, municipal buildings, enterprises, institutions, etc.

Batteries with chemical substances must be disposed of as follows:

Lithium, lithium-ion batteries and zinc batteries need to be disposed because they contain dangerous chemical components.

In addition, the standard AA batteries or the AAA, used in household appliances (cameras, mobile phones, laptops and instruments) also shall be disposed. See the markings of disposal on the batteries.

Car batteries, you should give for disposal in special collection points. Taking into account the cost of materials of the batteries, many companies selling cars and service centers are purchasing the car batteries with expired shelf-life for recycling.

Some distributors collect the batteries and electronic equipment for recycling.

Lead-acid elements (Lead Acid).

Today, gel lead-acid batteries are used in cars, trucks, and as backup power supplies.

However, in the mobile equipment they are used very rarely (and as portable batteries are used only elements of SLA-type), but are very widely used for stationary devices and communication systems, especially where needs a large capacity and reliability with significant temperature changes. Unlike lead-acid batteries with liquid electrolyte, gel batteries have a low capacity of charge and are developed with a substantial margin of loads, to prevent the appearance of gas bubbles during charge / discharge, which in turn causes the water depletion of the battery. For the same reason SLA- and VRLA-batteries can never be fully charged (intense charging in the final stage would cause saturation of the gases and the water depletion). However, they (as well as any other lead-acid batteries) should always be kept in a charged state to prevent increased sulphation.

Thus, all the SLA rechargeable batteries have the lowest energy density, making them unsuitable for small mobile devices. However, such batteries today – it’s the most economical and safest choice for large and powerful power sources, where size and weight are of secondary importance. Lead-acid batteries are used in medical equipment, for emergency lighting and are used in uninterruptible power systems (UPS). Large SLA-batteries for stationary applications have a capacity of 50 to 200 A • h.

All types of lead-acid batteries have approximately the same operating characteristics at low temperatures. Thus, at 0 ° C, they save about 95% of its capacity at room temperature, the temperature is lowered to -20 ° C the capacity decreases, but with a small load you can count on about 70% of the capacity at room temperature and at high load currents – about 50%.

It is important to remember that while the battery is operating at low temperatures, it does not mean that it can be charged under these conditions. Susceptibility to charge of the majority of batteries at very low temperatures is extremely limited, and the charge current in these cases should be reduced to one tenth of the nominal.

The optimum operating temperature for lead-acid batteries (such as SLA, and VRLA) about 25 ° C. Generally, a temperature rise on every 8 ° C shortens battery life by half. The battery, which would work for 10 years at 25 ° C, will operate only 5 years at a temperature of 33 ° C. And the same battery would not have worked for a year at a temperature of 42 ° C.

Unlike other types of batteries, lead-acid not like too frequent alternation of deep cycles of charge / discharge.

Depending on the depth of discharge and operating temperature of SLA-battery can withstand between 200 and 300 cycles of deep discharge / charge. The reason of the small number of cycles for these batteries – corrosion of the lead frame and the depletion / decomposition of the active material. Irreversible modifications of such type are most common when operating at high temperatures. Abrupt temperature changes also do not improve the situation.

Advantages of lead-acid batteries:

  • The ability to withstand large pulses of the current load;
  • Cheap and easy to manufacture; the most accessible and safe to operate – SLA-battery;
  • Well-developed, reliable and predictable technology – with proper operation – SLA-battery works very long;
  • Low operating cost;
  • The low self-discharge among all widely available rechargeable batteries;
  • With proper maintenance can withstand numerous surface (shallow) charge / discharge cycles;

Disadvantages of lead-acid batteries:

  • The lowest energy density per unit weight and volume compared to other batteries;
  • Can not be stored in a discharged state (full discharge causes the formation of sulphate and a loss of capacity, after which the battery can not be restored);
  • Can only be used where a deep discharge is an accidental phenomenon;
  • Although lead-acid battery has the highest capacity at temperatures above 30 ° C, but the long-term operation in such conditions reduces battery life;
  • Electrolyte and lead plates are harmful to the environment (but less than NiCd).

Nickel-Metal Hydride (Ni-MH) batteries.

Nickel-metal hydride (Ni-MH) batteries in its construction are analogues of nickel-cadmium (Ni-Cd) batteries, and in electrochemical processes – nickel-hydrogen batteries. Specific energy of Ni-MH battery is significantly higher than specific energy of Ni-Cd battery and hydrogen battery.

The development of nickel-metal hydride (Ni-MH) batteries began in the 50-70-ies. As a result, was established a new method of preservation hydrogen in nickel-hydrogen batteries, which were used in space vehicles.
In the new cell, the hydrogen is accumulated in the certain alloys of metals. Alloys absorbing hydrogen in 1000 times higher by their own volume, were found in 1960. These alloys are composed of two or more metals, one of which absorbs hydrogen and the other is a catalyst for promoting the diffusion of hydrogen atoms in the metal lattice. The number of possible used combinations of metals is not particularly limited, which makes it possible to optimize the properties of the alloy. To create a Ni-MH battery has required the creation of alloys workable at low hydrogen pressure and room temperature. Currently, the works of creation of new alloys and their processing technologies worldwide are continuing. The alloys of nickel with rare earth groups of metals can provide up to 2000 cycles of charge/discharges battery at low negative electrode capacity is not more than 30%.

The first Ni-MH battery, in which used as the main active material of a metal hydride electrode the alloy of LaNi5, was patented in 1975 Bill. But the industrial use of Ni-MH batteries began only in the mid 80-ies after the creation of the alloy of La-Ni-Co, allowing electrochemically reversibly absorb the hydrogen for over 100 cycles.

Basic processes of Ni-MH batteries.

In the Ni-MH battery as a positive electrode is used a nickel oxide electrode, as in the nickel-cadmium batteries, and electrode of alloy of nickel with rare earth metals that absorbs hydrogen, is used in place of negative cadmium electrode.

On the positive nickel oxide electrode of Ni-MH battery occurs reaction:

Ni (OH) 2 + OH- → NiOOH + H2O + e- (charge)
NiOOH + H2O + e- → Ni (OH) 2 + OH- (discharge)

On the negative electrode metal with the absorbed hydrogen becomes in the metal hydride:
M + H2O + e- → MH + OH- (charge)
MH + OH- → M + H2O + e- (discharge)
The general reaction in Ni-MH battery is as follows:
Ni (OH) 2 + M → NiOOH + MH (charge)
NiOOH + MH → Ni (OH) 2 + M (discharge)
The electrolyte is not involved in the main current-producing reaction.
After 70-80% of capacity, on the nickel oxide electrode starts to separate oxygen:
2OH- → 1 / 2O2 + H2O + 2e-
which is recovers on the negative electrode:
1 / 2O2 + H2O + 2e- → 2OH-
The last two reactions provide a closed oxygen cycle. When restoring oxygen is provided also an additional increasing of the capacity of metal hydride electrode due to the formation of OH group.

Characteristics of Ni-MH batteries.

Electrical characteristics.

The voltage of open circuit. The value of the open circuit voltage of Ni-MH-system hard to pinpoint because of the dependence of the equilibrium potential of the nickel oxide electrode on the degree of oxidation of nickel, as well as the dependence of the equilibrium potential of metal hydride electrode on the degree of saturation with hydrogen.

Rated discharge voltage at a specified discharge current Ip = 0,1-0,2S (C – nominal capacity of the battery) at 25 ° C is 1,2-1,25V, normal end voltage – 1V.

The capacity of the batteries. With increasing load (reducing the discharge time) and at low temperatures the capacity of Ni-MH battery decreases. Especially noticeable effect of temperature reduction on the capacity at high speeds of discharge and at temperatures below 0 ° C.