Academic tyrant: I have become a prodigy since I was able to pursue my academic career with peace of

Currently used lithium-ion batteries consist of three parts, namely lithium cobalt oxide positive electrode, carbon negative electrode and electrolyte.

During charging, lithium ions come out of the positive electrode, pass through the electrolyte, and reach the negative electrode. At the same time, electrons are transferred to the negative electrode through the external circuit, and the opposite is true during discharge. So, as the battery is charged and discharged again and again, lithium ions are constantly traveling back and forth between the two poles. There have been no major changes to this system for decades since it was developed.

Chen Fan came to the laboratory, woke up Xiaoqiang, and"looked for information about batteries.""

"Found it. There are a total of 1357 books and various materials for dad to refer to and explore."

"good."Chen Fan began to study.

As far as he is concerned, the current lithium ions are like Sisyphus in Greek mythology, and like the dog traveling between AB and AB in the math problem, running around like this day after day.

But at the same time, there are Lithium-ion battery technology faces three problems, namely low energy density, potential safety hazards, and too high cost.

First, energy density is one of the most important indicators for evaluating batteries of the same quality.

The one that can store more electrical energy has a higher energy density.

The Department of Energy once planned a roadmap for lithium-ion batteries.

It was originally hoped that the energy density of lithium-ion batteries could reach this value of

400 watt-hours per kilogram.

This means that existing electric vehicles can continue to run for more than 500 kilometers on a single charge. However, the best commercial lithium-ion batteries currently only reach 75% of expectations.

Secondly, in terms of safety, lithium-ion batteries have long been under scrutiny. People have criticized it. Especially the explosion of the five-star mobile phone in Hanguo has brought lithium- ion batteries to the forefront.

The safety hazard of lithium batteries comes from their sensitivity to high temperatures. Generally speaking, the operating temperature of lithium battery equipment needs to be below 60°C.

During the safety test, the factory will place the battery in an 80°C environment for high-temperature durability testing. If there is no obvious deformation or fire , it is considered qualified. There is also a more extreme condition called the thermal abuse test: the battery is placed at 130°C. ℃ test chamber, if it does not catch fire for half an hour, it is considered to have reached the safety standard.

Then there is the high cost of batteries. According to the existing data, the price of lithium carbonate, the main raw material of lithium batteries, only took half a year It has increased by 2.5 times. Back then, it would have been more profitable to buy a dozen tons of lithium carbonate than to speculate on real estate. Second, the production of lithium batteries has not yet been scaled up, and all major manufacturers are working on their own issues.

Ion batteries are on the road to the future, so it is imperative to develop new batteries.

One hour.

Two hours. Three hours.

It is difficult to understand and memorize knowledge points.

For a moment.

The air conditioner suddenly stopped.

"Dean Chen, the switch is burned out, and the technical team is currently repairing it."The people from the Panda Team shouted inside.

"knew."Chen Fan didn't even raise his head. The experiment he was going to do now did not require electricity.

But without the air conditioner, the board room was too hot. He felt like he was soaking in a steam room, sweat dripping down his face.

There was no trembling in his hands. There is no need to complain about being tired.

Science is inherently tiring. Behind the birth of a truth and a new thing is the success of scientists working day and night.

"Who can achieve the goal better, Xiaoqiang, sodium-ion battery, multi-ion battery, or metal-air battery? what is the reason." Chen Fan asked.

These three types of batteries are the last possible replacements for lithium batteries in the future. First, the working principle of sodium (Na) ion batteries is similar , except that the carrier of charge is replaced by sodium ions.

The largest use of sodium The advantage is that it is abundant. The total reserves of sodium are 400 times that of lithium. Sodium (Na) is the most common alkaline metal and the sixth most abundant element on the earth.

In addition, there is a very important component in the battery called set. Fluid is used to collect the generated current and then supply the current to the external circuit.

The material of the current collector in sodium-ion batteries is aluminum, and aluminum will corrode in lithium batteries, so the current collector of lithium-ion batteries can only use copper. To make.

The price of aluminum is one-third of the price of copper. Therefore, sodium itself is cheap, and its partners are also very cheap. This feature contributes to the huge cost advantage of sodium-ion batteries. In the ionic state, the valence state of lithium element is +1, which means that each movement of it can carry one charge, corresponding to the transfer of one electron. Therefore, when the number of lithium is n, the number of charges that this battery can store. The upper limit is 1*n.

What if an ion can carry multiple charges at the same time? For example, the valence state of magnesium (Mg) is +2, and theoretically, the same amount of magnesium can be used. The number of charges that magnesium-ion batteries can store is twice that of lithium-ion batteries. Aluminum (Al) ions are more powerful and can carry three charges at the same time.

Based on this principle, batteries using high-valence metal ions, that is, Multi-ion batteries.

Because the same number of ions can store a higher density of charge, multi-ion batteries tend to achieve higher energy densities.

In addition, the electrolyte used in lithium-ion batteries is an organic solution, which is flammable and toxic. Multi-ion batteries use different electrolytes and are safer.