Tesla's new solid-state battery breakthrough: a pinch of baking soda solves battery life issues

Elon Musk, the "alchemist", has just made a 0-1 breakthrough in the field of solid-state batteries .

Tesla's latest patent is open to the public, which talks about how new materials can improve the cycle life of batteries.

How much has it improved? About 10%.

Not too impressive?

But Tesla's new achievement is to make a battery positive electrode material that was previously only feasible in theory a reality for the first time, opening a new door for the development of subsequent solid-state battery technology .

The application of new materials may rewrite the energy field again.

What’s so great about Tesla’s new battery material?

Let’s look at the experimental results first:

After 50 charge and discharge cycles, the total capacity of the battery made of Tesla's new positive electrode material decayed to about 94%.

In the comparative experiment, the total capacity of the battery that did not use Tesla's new formula decreased by about 10%.

If calculated by absolute mileage, 50 charge and discharge times would roughly translate to about 20,000 kilometers of vehicle usage.

Therefore, if we put it into the real situation of ordinary family cars with a range of at least 60,000-70,000 kilometers or even 100,000 kilometers, the improvement of battery degradation by Tesla's new cathode material is actually very limited. In other words, it is still a long way from being put into mass production.

However, the power of Tesla's new patent is that it breaks through a long-standing problem in the battery industry - manganese-rich positive electrode materials.

The solution is to sprinkle a pinch of baking soda.

Solid-state batteries are being used in cars, is baking soda useful?

As for batteries, everyone is familiar with them. The main principle is that the redox reaction is realized in a closed loop.

The discharge process of the battery is that the positive electrode of the battery, which is composed of an oxidant with a relatively positive potential and stable in the electrolyte, obtains electrons in the reaction, which means that the electrons on the negative electrode reach the positive electrode through the electrolyte , reducing the positively charged ions, and releasing energy in the process.

Charging is the opposite oxidation reaction.

Positive electrode - electrolyte - negative electrode, this basic structure has never changed since Volt invented the battery in 1799.

Any innovation related to batteries is an alchemy of these three parts.

For example, the currently popular concept of solid-state batteries replaces the liquid electrolyte in traditional batteries with solid electrolytes, thereby achieving the characteristics of small size, large capacity, and fast charging and discharging.

However, the improvement of battery performance is not only at the electrolyte level, the innovation of positive and negative electrode materials is also very critical.

For example, the most common ternary lithium or lithium iron phosphate batteries are named after the positive electrode materials.

Generally speaking, the positive electrode of the ternary lithium battery is lithium nickel cobalt manganese oxide (Li(NiCoMn)O2) or lithium nickel cobalt aluminum oxide, and the negative electrode is graphite material. Its advantages are high energy density, fast charging and discharging speed, and light low-temperature attenuation.

But the disadvantages are also obvious, the cost is high, mainly because the reserves of cobalt on earth are far less than manganese or nickel.

Therefore, the high nickel content of ternary lithium batteries is the direction we are pursuing now. However, the static mining cycle of nickel mines in the world is only about 35 years.

Lithium iron phosphate batteries have many advantages in terms of cost, but their battery life and resistance to attenuation are not as good as ternary lithium.

Is there any positive electrode material that can balance energy density and cost?

There are many attempts now, one of which is manganese-rich positive electrode materials, such as LiMn2O4 - lithium manganese oxide, which was first artificially synthesized in 1981 and is a positive electrode material with three-dimensional lithium ion channels.

Needless to say, the reserves of lithium and manganese on the earth are far higher than those of cobalt and nickel (the difference between billions of tons and millions of tons), so the cost problem is solved.

In addition, lithium manganese oxide has the advantages of high potential, environmental friendliness, and high safety performance. It is recognized as the most promising cathode material to replace lithium cobalt oxide LiCoO2 and become the new generation of lithium-ion batteries .

In the next generation of solid-state battery technology, the combination of manganese-rich positive electrode materials and composite lithium metal negative electrodes has become a route that is widely favored for mass production prospects.

But~ there is always a "but" in everything. Manganese-rich positive electrode materials, including lithium manganese oxide, have a fatal flaw, that is, the battery capacity decreases quickly and the battery life decays seriously.

The mechanism involves multiple factors. On the one hand, during the charge and discharge process, manganese ions tend to dissolve into the electrolyte, resulting in a decrease in the manganese content in the material, which in turn causes voltage decay.

On the other hand, the structural destruction of the positive electrode material is also an important factor in voltage decay. During the charging and discharging process, the lithium-rich manganese-based positive electrode material will undergo volume changes, resulting in crystal strain and fracture, thereby destroying the material structure and further causing voltage decay.

So the method can also start from these two aspects.

Tesla's new patent uses a method of doping with an appropriate amount of transition metal ions to improve the quality and stability of the material.

Reduce dissolution and precipitation, thereby reducing voltage decay.

Generally speaking, metal ions such as zinc, iron, and nickel can be doped. However, considering the fundamental demand of "reducing battery costs", Tesla chose to dope magnesium (magnesium fluoride) and sodium (sodium carbonate).

Magnesium fluoride may not be commonly used by ordinary people. It is generally used in metallurgy, ceramics, and optics. But we are very familiar with sodium carbonate, which is baking soda.

Of course, the sodium carbonate here is an industrial-grade product, and its purity is very different from the baking soda in your and my kitchen.

Although Tesla's new patent is only a small step towards the use of manganese-rich positive electrode materials in vehicles, its significance cannot be underestimated:

Turning a battery positive electrode material that was previously only available "in theory" into reality.

If used in current liquid batteries, it can significantly reduce costs and improve performance.

But what is more important is the application of solid-state batteries in the future: in terms of the positive electrode, low-cost, high-performance manganese-rich materials can naturally meet the needs, and now Tesla has provided an equally low-cost solution to the battery life problem.

Cracking Electric Vehicles The key breakthrough in the seemingly impossible triangle of battery life, cost, and performance has been quietly lying in our kitchens.

Academician Musk now has a new title: Alchemist.