Plugging into the power of polymers: lithium-ion and other battery technologies will increasingly be getting more solid support and energy density from polymers.
On, 24/7 lifestyle powered by lithiumion(Li-
Without batteries, from laptops to tablets to smartphones, we will not be able to use all our portable electronic devices.
However, anyone who uses these portable electronic devices knows,
There is no problem with the ion battery.
First of all, they still need to charge regularly, especially as our electronics become more and more powerful, so the power supply-
It usually takes a few hours.
In addition, their energy capacity has gradually declined over time, which requires them to train more and more often until eventually they need to relocate.
Solving these problems is not only beneficial to the users of electronic devices, but also contributes to the wide application of electric vehicles and renewable energy.
Ideally, an electric car needs a battery that is strong enough to withstand the same charging distance as a tank full of gasoline.
Renewable energy technologies, such as solar and wind energy, require batteries to be able to effectively store excess energy generated in the event of sunlight or strong winds, and then release it quickly without sunlight or strong winds.
Researchers in academia and industry are working to explore ways to solve these problems and improve them.
And developing alternative battery technologies.
Polymer is at the heart of many of these efforts. The Guts of Li-
Ion battery with any battery, Li-
The ion battery consists of a negative electrode (anode) and a positive electrode (cathode) separated by a liquid electrolyte.
When energy is released, the lithium ion passes through the electrolyte from the anode to the cathode, driving the associated electron flow through the external circuit.
When the battery is charged by an external power supply, this process is reversed, and the opposite electron flow drives the lithium ion from the cathode to the anode.
The amount of a Li-charge
The capacity of the ion battery depends on how much lithium ion can be stored in each electrode.
The power that the battery can generate when discharging and the speed of charging depends on the speed at which the lithium ion passes through the electrolyte.
In the current generation
For ion batteries, the anode is graphite, while the cathode is a metal oxide, such as lithium cobalt oxide or manganese oxide.
The liquid electrolyte consists of a lithium six-Fluorine Phosphate salt dissolved in organic solvents such as ethylene carbonate or propylene carbonate.
Researchers know several substances that can make better electrode materials for Li-
But there is a problem with each battery.
Pure lithium metal anode is better than graphite anode, sulfur-
Since more lithium ions can be stored in both theory, cathode-based batteries will be better than metal oxides.
The problem with lithium metal anode is that the arrival rate of lithium ion is often faster than they are incorporated into the anode, thus accumulating into deposits on the surface.
In enough time, these deposits, known as shoot crystals, can be extended directly through the electrolyte to the cathode, causing the battery to be short-circuited.
These branches are also formed on the graphite anode, but they are more of a problem with the lithium metal anode.
The problem of sulfur-
Based on the cathode, the sulfur and lithium reactions produce various compounds dissolved in the electrolyte, pollute it and cause sulfur-
The electrodes degrade over time.
However, the liquid electrolyte becomes a solid polymer, both of which can be solved by replacing the liquid electrolyte with a solid polymer electrolyte, this will physically prevent the diffusion of shoot crystals and the dissolution of compounds produced by sulfur and lithium reactions.
There are several other advantages of solid polymer electrolyte.
First of all, they will be safer because of the liquid electrolysis used in the current Li-
The ion battery is flammable and is known to catch fire if the battery is too hot.
They can also make flexible batteries of various shapes, as the liquid electrolyte does not need to be packed in a sturdy package.
(This package is usually made of polymer, the current Li-
Ion batteries are sometimes called Polymer Li-
Ion batteries, even if they contain liquid electrolyte.
) Conductive polymers such as polyethylene oxide (PEO) doped with lithium ions show the prospect of being a solid polymer electrolyte, but scientists have been working hard to develop PEO materials that can transport lithium ions to anywhere nearby and
Still, several companies, including the United StatesS.
Seeo and SolidEnergy are actively developing advanced versions of Li-
Ion batteries containing solid polymer electrolyte.
Seeo\'s polymer electrolyte technology, known as DryLyte, was initially developed by researchers at Lawrence Berkeley National Laboratory.
Seeo combines DryLyte with a lithium metal anode to produce electric vehicle batteries and claims that the energy density of these batteries is 350 W.
Hourly per kilogram
This is easier to understand than the energy density of traditional Li-
Ion batteries, and can take an electric car with one charge until it is filled with gasoline.
(Bosch, a German technology company, is clearly convinced that it acquired Seeo in September 2015.
) The Solid Energy is a spin-
It is developing an advanced Li-
The ion battery combines the super
Thin metal anode made of thin lithium and solid polymer electrolyte on copper.
The company claims that its advanced battery also has about twice the energy density of conventional batteries. ion battery.
At the same time, academic researchers at PEO are busy looking for more innovative ways to prepare PEO into a solid electrolyte.
For example, chemical engineers at Cornell University
Chain poly-monomer onto silica particles and connect these particles with polypropylene oxide.
This creates a cross-linked nanoparticles.
Then the polymerization composites soaked in traditional liquid electrolysis are prepared to prepare lithium salts dissolved in propylene carbonate.
(1) the biggest advantage of this cross-linking structure is that it creates a porous conductive channel system that lithium ions can pass through almost as easily as through conventional liquid electrolyte.
Combining this composite with lithium metal anode and metal oxide creates a battery that holds high current density and discharge capacity in more than 150 charge/discharge cycles.
PEO can also help develop the most promising lithium-based battery.
This is lithium-
Air battery with oxygen as cathode.
Apart from being much lighter than traditional Li
Lithium ion battery (because it no longer has the weight of a solid cathode), lithium-
The energy of the air battery is ten times that of the theoretical energy.
This is because they are not incorporating lithium ions into solid materials, but are stored by a reduction reaction with oxygen that produces hydrogen peroxide.
Unfortunately, over time, this process will also produce oxygen free radicals that gradually oxidized liquid electrolyte, which means lithium-
Air batteries tend to stop working after several charge/discharge cycles.
However, two chemists at SapienzaUniversity in Italy recently discovered that,
Lithium ion-doped base material is a very effective lithium solid electrolyteair batteries.
(2) This is not only a plastic-enhanced PEO-
Based on chemically stable materials, it is prevented from being oxidized by oxygen free radicals, but it is also more conductive than most other solid electrolyte developed by peo.
When used with a lithium metal anode, this plasticized PEO produces lithium-
Air cells with a possible energy density of more than 300 watts-
Hourly per kilogramRedox-
Polymer-based batteries are not the only option in the battery because there is an alternative battery technology that can remove not only lithium, but also solid electrodes.
A mobile battery, which works by flowing two liquids, each containing ions that can exist on either side of the proton in one of two oxidation states
When ions in each liquid move between the oxidation states, they push the protons through the membrane and drive the associated electron flow through an external circuit.
Charging the battery from an external power supply reverses the flow of electrons and protons, causing the ion to return to its original oxidation state.
The liquid is kept in an external tank and then pumped over the membrane.
This means the energy capacity of redox-
Flow cells can be increased by increasing the size of the tank, which makes them excellent battery technology for storing excess energy generated by wind and solar energy.
Oxidation and reduction of most-
Up to now, the mobile battery system installed for this purpose uses vanadium ions, heavy metals and water wells-
The state of perfluoride polymer known as membrane.
Because ions can exist in one of the four oxidation states, they can be used in both liquids, and the ions in each liquid alternate between different one-to-one oxidation states.
Unfortunately, vanadium is as expensive as the national film, and this cost hinders redox-flowbatteries.
In addition, vanadium ionic liquids are produced by dissolving vanadium salt in sulfuric acid, which is highly corrosive and limits the life of the battery.
The use of sulfuric acid also explains why a firm, expensive membrane like the state is needed.
However, recently, a team of chemists from the University of jena
Off company from Yena Battery University found two oxidation-reduction-
Active polymer is also effective.
In addition to being much cheaper than vanadium, these polymers can also be dissolved in salt water instead of sulfuric acid, so that the national membrane can be replaced by a cheaper cellulose membrane.
Their initial oxidation-reduction-
The energy density of the mobile battery is only 10 watts.
Hours per liter, but it can withstand charging/discharging cycles up to 10,000 times without losing any of this capacity.
The team is already working on a larger and more efficient system. -
All of this will help ensure that our electronic devices remain charged in the future. References(1.
) Natural Communications, 2015, 6, 10101 (Earth well: 10.
1038/ncomms10101 ). (2.
) Scientific report, 12307, (DOI: 10. 1038/srep12307 ). (3.
) Nature, 2015,527, 78-81 (DOI: 10.