CATL M3P Deep Dive // The Manganese Demons

Welcome back everyone, I'm Jordan Geisigee, and this is The Limiting Factor. In the last video of the LFP series, I covered CATL's M3P chemistry from the perspective of cycle life, cost, and energy density. That is product level questions, but I also briefly mentioned in that video that CATL's M3P battery chemistry appears to be an L MFP type chemistry. That is, an LFP chemistry doped with manganese to increase its energy density. The question is, if it was just a matter of adding manganese to increase the energy density of LFP, why wasn't that done earlier? The short story is that batteries are complex, multi-scale, multi-physics systems, which means there's always demons in the machine that have to be exercised to bring a new chemistry to market. So today, I'm going to explain what those specific demons are for L MFP and how CATL may have solved them with their M3P chemistry. Before we begin, a special thanks to my Patreon supporters, YouTube members, and Twitter subscribers, as well as RebellionAir.com. They specialize in helping investors manage concentrated positions. RebellionAir can help with covered calls, risk management, and creating a money master plan from your financial first principles.

大家好，欢迎回来，我是乔丹·盖西吉，这里是《限制因素》节目。在上一期LFP系列的视频中，我从循环寿命、成本和能量密度的角度讨论了CATL的M3P化学成分。这是产品层面的问题，但我在那个视频中也简要提到CATL的M3P电池化学成分似乎是一种L MFP类型的化学成分。也就是说，一种含有锰掺杂的LFP化学成分以增加其能量密度。问题是，如果只是加入锰来增加LFP的能量密度，为什么之前不这样做呢？简短的故事是，电池是复杂的、多尺度的、多物理学系统，这意味着总会有需要解决的困难问题才能将新的化学成分推向市场。所以今天，我要解释一下L MFP的具体问题是什么，以及CATL如何通过他们的M3P化学成分解决了这些问题。在我们开始之前，特别感谢我的Patreon支持者、YouTube会员和Twitter订阅者，以及RebellionAir.com。他们专门帮助投资者管理集中的头寸。RebellionAir可以帮助您进行期权买卖、风险管理，并根据您的金融第一原则创建一个金钱大师计划。

In order to understand CATL's M3P chemistry, let's work from the known to the unknown. Most people who follow batteries are familiar with the LFP chemistry. LFP stands for Lithium Ferro-phosphate, or in more common language, Lithium-iron phosphate. In the last video of the LFP series, I said that the crystal structure of L MFP is the same as LFP except that some of the iron is swapped for manganese. The manganese increases the voltage potential of the LFP, and it's the reason why L MFP can have up to 15-20% higher energy density than LFP. However, the addition of the manganese creates electronic conductivity issues, yawn teller effects, dissolution issues, and ionic conductivity issues. Let's walk through each.

为了了解CATL的M3P化学结构，让我们从已知到未知进行研究。许多关注电池的人都熟悉LFP化学结构。LFP代表锂铁磷酸盐，或者更常见的说法是亚铁锂磷酸盐。在LFP系列的最后一个视频中，我说过L MFP的晶体结构与LFP相同，只是一些铁被锰替代。锰增加了LFP的电压潜力，这也是为什么L MFP的能量密度可以比LFP高15-20%的原因。然而，添加锰会引起电子导电性问题、约翰泰勒效应、溶解问题和离子导电性问题。让我们逐一讨论这些问题。

Starting with electrical conductivity, as I explained in the LFP science video, LFP has poor electrical conductivity because the iron atoms in the crystal structure are too far apart to conduct electricity. The way that was solved was by adding conductive carbon coatings to the cathode particles, and by making the cathode particles smaller, which reduces the distance that the electrons have to travel through the cathode material. Making manganese makes the electrical conductivity even worse. Additionally, manganese is resistant to the carbon coating process. The solution to that is to limit the amount of manganese used in L MFP batteries, and it's one of the reasons why not all the iron in the LFP crystal structure is swapped out for manganese. By leaving some iron in the crystal structure, around 20-50%, rather than completely replacing it with manganese, it minimizes the electrical conductivity challenges of using manganese, while still providing most of its increased voltage and energy density benefits.

从电导率开始，正如我在LFP科学视频中所解释的那样，LFP的电导率很差，因为晶体结构中的铁原子间距太远而无法导电。解决这个问题的方法是通过在正极颗粒上添加导电碳涂层，并使正极颗粒变小，从而减少电子在正极材料中传输的距离。锰的加入会使电导率变得更糟。此外，锰对碳涂层过程具有抵抗力。解决这个问题的方法是限制在LFP电池中使用的锰的量，这也是为什么并不是所有LFP晶体结构中的铁都被替换为锰的原因之一。通过在晶体结构中留下大约20-50%的铁，而不是完全用锰替换它，可以最大程度地减少使用锰所带来的电导率挑战，同时仍能提供大部分增加电压和能量密度带来的好处。

Besides improving electrical conductivity, leaving some iron in the cathode also helps with yawn teller effects and dissolution issues. Let's get into those now, starting with the basics of how a cathode works. Before the battery cell is charged, with an L MFP chemistry, the state of charge of the manganese atoms in the cathode are 2+. Then, when the battery cell is charged, the charge of the manganese atoms changes to 3+. Both of those charge states, 3+, and 2+, cause degradation in the cathode that reduces cycle life. First, manganese 3+, is subject to yawn teller effects. What are yawn teller effects? All atoms have electrons which configure themselves in orbitals around the atom. In some electron configurations and some metallic elements, when the charge state of the atom changes by gaining or losing an electron, the orbitals become unbalanced because the energy is no longer distributed evenly, and the shape of the orbitals becomes distorted. If the atom is part of a crystal, the distortions in the shape of the orbitals changes the angles and distances between that atom and the other atoms in the crystal structure, which in turn distorts the shape and volume of the crystal structure. When the shape and volume of the crystal structure changes, the cathode particle that the crystal is part of can fracture. Those fractures open up fresh surface area which can react with the electrolyte, causing degradation and reduced cycle life. Second, as for manganese 2+, it's attracted to and dissolves into the electrolyte. Some of those manganese 2+, ions make their way to the graphite anode, where two things can happen. First, the manganese 2+, ion can react with the solid electrolyte interface, which causes degradation that reduces cycle life. For the purposes of today's video, the solid electrolyte interface is just a protective chemical layer on the anode that makes the battery last longer. Second, the manganese 2+, can deposit as metallic manganese that can short out the battery cell, which is a safety issue.

除了提高电导率外，将一些铁留在阴极中还有助于避免尹泰勒效应和溶解问题。现在让我们详细讨论一下这些问题，首先从阴极工作的基础知识开始。在充电之前，使用L MFP化学反应的电池单元中，阴极中锰原子的电荷状态为2+。然后，在充电时，锰原子的电荷变成3+。这两种电荷状态，3+和2+，都会导致阴极降解，从而降低循环寿命。首先，锰3+会受到尹泰勒效应的影响。什么是尹泰勒效应？所有的原子都有电子，这些电子围绕原子的轨道排列。在某些电子配置和某些金属元素中，当原子的电荷状态通过获得或失去一个电子而改变时，轨道变得不平衡，因为能量不再均匀分布，轨道的形状会变得扭曲。如果原子是晶体的一部分，轨道形状的扭曲会改变该原子与晶体结构中其他原子之间的角度和距离，从而扭曲晶体结构的形状和体积。当晶体结构的形状和体积发生变化时，晶体的阴极颗粒可能会破裂。这些裂缝会打开新的表面积，可以与电解液发生反应，导致降解和减少循环寿命。其次，对于锰2+，它会被电解液吸引并溶解到其中。其中一些锰2+离子会进入石墨阳极，发生两种情况。首先，锰2+离子可以与固体电解质界面发生反应，导致降解并降低循环寿命。在今天的视频中，固体电解质界面只是阳极上的一种保护化学层，使电池寿命更长。其次，锰2+可以沉积为金属锰，会短路电池单元，这是一个安全问题。

Now that we know how manganese causes yawn teller effects and dissolution issues in LMFP cathodes, what are the engineering solutions to get around those issues? This brings us to CATL's M3P chemistry. Reporting out of China suggests that besides being an LMFP chemistry, CATL's M3P chemistry replaces some of the iron ore manganese with magnesium, aluminum and zinc. I don't have confirmation with a tear down that those elements are accurate, but they do make sense, because those elements are often used to stabilize cathodes and improve their cycling performance.

现在我们知道锰是如何导致LMFP阴极产生“打哈欠”效应和溶解问题的，那么如何解决这些问题呢？这就引出了CATL的M3P化学体系。中国的报告显示，除了是LMFP化学体系之外，CATL的M3P化学体系用镁、铝和锌部分取代了铁矿锰。我没有解体验证这些元素是否准确，但这是合情合理的，因为这些元素通常用于稳定阴极并提高它们的循环性能。

Rather than going through each doping element, I'm going to focus on magnesium. Note that aluminum and zinc may do a better job of reducing yawn teller effects, which is why they may have been added in addition to magnesium. It's since there's more and better research on magnesium, and it likely operates in the same way to reduce yawn teller effects as aluminum and zinc, magnesium is what I'm going to cover. So how does magnesium reduce yawn teller effects? Instead of participating in the electrochemical reactions when the battery is charging and discharging, it remains in the same charge state, while the electrochemically active manganese and iron cycle back and forth between 2 plus and 3 plus charge states. That has an anchoring effect on the crystal structure and prevents it from warping.

与逐个讨论每种掺杂元素不同，我将专注于镁。请注意，铝和锌可能在减少打哈效应方面做得更好，这就是为什么它们可能被添加到镁之外的原因。由于对镁有更多和更好的研究，并且它很可能以与铝和锌减少打哈效应相同的方式发挥作用，因此我将涵盖镁。那么镁是如何减少打哈效应的呢？在电池充电和放电时，它不直接参与电化学反应，而是保持相同的电荷状态，同时电化活性的锰和铁在2加和3加电荷状态之间往复循环。这对晶体结构有锚定效应，并防止其变形。

That effect is so strong that it only takes doping with a few percent of magnesium to anchor the crystal structure. However, magnesium has another beneficial effect for LMFP. It improves the ionic conductivity of LMFP, which tends to be poor compared to LFP. For the purposes of this video, by ionic conductivity, I mean how quickly and easily lithium ions can move through the cathode crystals when the battery cell is charged or discharged. The way magnesium improves the ionic conductivity is by modifying the bond lengths and angles within the crystal structure. The image on screen shows a pure LMFP octahedron on the left and a magnesium doped LMFP octahedron on the right. One of the angles on the LMFP is 108.98 degrees and the corresponding angle on the magnesium doped version is 104.58 degrees. Why is that important?

这种效应非常强大，以至于只需添加少量的镁就能锚定晶体结构。然而，镁对于锂铁磷酸锂（LMFP）还有另一个有益作用。它改善了LMFP的离子导电性，这在与磷酸铁锂（LFP）相比往往较差。在本视频中，通过离子导电性，我指的是当电池电池充电或放电时锂离子在阴极晶体中移动的速度和便捷程度。镁如何改善离子导电性是通过修改晶体结构内的键长和角度。屏幕上的图像显示了左侧的纯LMFP八面体和右侧的掺镁LMFP八面体。LMFP上一个角度为108.98度，相应的镁掺杂版本上的角度为104.58度。这为什么重要？

Zooming out to the broader crystal structure, we can see nine of the octahedra that were shown in the last image, but this time in the context of the rest of the crystal structure. When the battery is charged and discharged, the lithium ions wiggle their way through the crystal structure. By changing the angles and the lengths of the bonds within the octahedra with magnesium, it creates a slight change to the crystal structure. That in turn creates a smoother path for the lithium ions to flow into and out of the crystal structure, which means more lithium is available for cycling when the battery charges and discharges, meaning more energy. The question is, how much of an impact does doping with magnesium have on the energy capacity of the cathode?

放大到更广泛的晶体结构中，我们可以看到在上一张图片中展示的九个八面体，但这次是在晶体结构的其他部分中。当电池充电和放电时，锂离子会穿过晶体结构摆动。通过改变与镁结合八面体内的角度和长度，它对晶体结构造成了轻微的改变。这反过来为锂离子创造了更顺畅的路径，使其能够更容易地流入和流出晶体结构，这意味着在电池充电和放电时更多的锂可用于循环使用，也就是更多的能量。问题是，镁掺杂对正极的能量容量有多大影响？

The graph on screen shows that the net result of magnesium doping is an increase in capacity from 134.1 milliamp hours per gram to 146.4 milliamp hours per gram, or about a 9% improvement. Not bad for swapping out just 4% of the electrochemically active iron with inactive magnesium. Finally, what about the dissolution issues with manganese 2+, those can be mitigated and possibly even solved by layering 3-4 engineering fixes for the cathode. First, as I said earlier, only about 50-80% of the iron is swapped out for manganese in LMFP chemistries. The iron is much less likely to dissolve in the electrolyte than the manganese, so one of the ways to reduce the dissolution issues is to stick closer to 50% iron in the cathode formulation. However, that doesn't fundamentally solve the dissolution issues. It only reduces them.

屏幕上的图表显示，镁掺杂的净结果是电容从每克134.1毫安时增加到每克146.4毫安时，或者约提高了9%。仅用无活性镁替换了电化学活性铁的4%，效果不错。最后，对于钠2+的溶解问题，这些可以通过对正极进行3-4个工程修复来缓解甚至可能解决。首先，正如我之前所说，LMFP化学中只有50-80%的铁被替换为锰。铁溶解在电解质中的可能性远低于锰，因此减少溶解问题的一种方法是在正极配方中更接近50%的铁。然而，这并不能从根本上解决溶解问题，只是减少了它们。

The second way to reduce dissolution is to prevent the cathode particles from fracturing. As we saw earlier, young teller effects can cause the cathode crystal structure to distort, which in turn can cause the cathode particles to crack. As they fracture, it exposes more cathode surface area for the manganese to dissolve into the electrolyte. But as I showed, elements like magnesium, aluminum, and zinc can be used to anchor the crystal structure, which should reduce distortions in the crystal structure from young teller effects and therefore reduce cracking. That is, using doping elements like magnesium to solve the young teller effects simultaneously helps with the dissolution issues. But again, this fix still isn't a fundamental and direct fix to the dissolution issues. It just mitigates the dissolution issues.

第二种减少溶解的方法是防止阴极颗粒破裂。正如我们之前所看到的，杨氏效应可能导致阴极晶体结构变形，进而导致阴极颗粒碎裂。当它们破裂时，会暴露更多阴极表面积使锰溶解到电解液中。但正如我所展示的，镁、铝和锌等元素可以用来锚定晶体结构，从而减少由于杨氏效应引起的晶体结构扭曲，减少开裂。也就是说，使用镁等掺杂元素来解决杨氏效应同时有助于处理溶解问题。但是，这种解决方法仍不是根本和直接解决溶解问题的方法，它只是减轻问题。

Let's take a look at a more direct and fundamental solution to the dissolution challenge. Particle Engineering For the purposes of today's video, there are two engineering solutions that can modify the cathode particles so that the manganese is isolated from the electrolyte. The first option, increasing the thickness of the carbon coating used on the cathode particles, would be a simple fix. But because the carbon coating doesn't store energy, it would reduce the energy density of the cathode. So this is an option, but not the best option. The second option, a concentration gradient structure for the cathode particles, involves growing the cathode particles in a way that results in a high ratio of iron to manganese near the surface of the cathode particle and a lower ratio of iron to manganese towards the core of the particle. That is, the bulk of the soluble manganese is safely tucked away in the core, which reduces the chances that it'll come into contact with the electrolyte and dissolve into it.

让我们来看一种更直接和基本的解决溶解挑战的方法。粒子工程针对今天的视频来说，有两种工程解决方案可以修改阴极粒子，使得锰与电解液隔离开来。第一种选择是增加用于阴极粒子的碳涂层的厚度，这将是一个简单的修复方法。但是因为碳涂层不能储存能量，这将降低阴极的能量密度。所以这是一个选项，但不是最佳选项。第二个选择是阴极粒子的浓度梯度结构，涉及以一种使从阴极粒子表面到核心逐渐增加以铁和锰比例很高的方式生长阴极粒子。也就是说，大部分可溶解的锰安全地隐藏在核心中，从而降低了它与电解液接触并溶解入其中的机会。

In my view, this makes the concentration gradient option the most effective way to isolate the manganese from the electrolyte while not requiring any additional mass or material like the carbon coating option. So I expect this is the option that most LMFP battery producers will choose. The drawback to the concentration gradient option is that it requires a more complex and expensive process to produce the cathode particles. As I said in my Battery Roadmaps video, LMFP battery cells like CATL-M3P are currently estimated to cost about 5% more than LFP battery cells. With that said, over time, through economies of scale and due to the fact that LMFP batteries are more energy dense and therefore require less material, LMFP batteries should end up costing less.

在我看来，这使得浓度梯度选择成为从电解液中分离锰最有效的方式，而不需要任何额外的质量或材料，如碳涂层选项。因此，我预计这是大多数锂金属锰铁磷酸盐(LMFP)电池生产商将会选择的选项。浓度梯度选择的缺点是需要一个更复杂和昂贵的过程来生产阴极颗粒。正如我在我的电池发展路线图视频中所说的，像CATL-M3P这样的LMFP电池目前估计成本比磷酸铁锂(LFP)电池高出约5%。话虽如此，随着时间的推移，通过规模经济和由于LMFP电池能量密度更高，因此需要更少的材料，LMFP电池的成本应该会降低。

In summary, although it seems there's only a small difference between LFP and LMFP battery chemistries at a conceptual level, where some of the iron is swapped out for manganese, LMFP is much more challenging to commercialize due to things like Yonteller effects and dissolution issues. Those issues mean that even though adding manganese to an LFP chemistry can increase energy density by up to 15-20% and do so at a similar cost to LFP batteries, which creates a big market opportunity, it's taken about 10-15 years of research to bring the chemistry to market.

总之，虽然在概念上LFP和LMFP电池化学成分之间似乎只有很小的区别，其中一些铁被锰替代，但是由于诸如Yonteller效应和溶解问题等原因，LMFP更具挑战性的商业化。这些问题意味着即使将锰添加到LFP化学体系中可以使能量密度提高15-20％，并且成本类似于LFP电池，从而创造了巨大的市场机遇，但将这种化学体系推向市场却需要约10-15年的研究。

However, even with the energy density and cost benefit that LMFP batteries have over LFP batteries, my view is that LFP will likely maintain some advantages over LMFP chemistries, such as cycle life. That's for a number of reasons, but let's look at just two. First, LFP batteries operate at lower voltages and in a narrower voltage range, meaning they're more electrochemically stable. Second, I suspect that some of the manganese in the concentration gradient cathode particles will still find a way to dissolve into the electrolyte solution and react with the anode to reduce battery life. That could occur as a result of manufacturing imperfections or from fracturing that occurs in the cathode particles during cycling.

然而，尽管LMFP电池在能量密度和成本效益方面优于LFP电池，但我认为LFP电池可能仍保持一些优势，比如循环寿命。这有很多原因，但我们只看其中两个。首先，LFP电池在较低的电压下工作，电压范围较窄，这意味着它们在电化学上更稳定。其次，我怀疑浓度梯度阴极颗粒中的一些锰仍会溶解到电解质溶液中，与阳极发生反应，从而降低电池寿命。这可能是由制造缺陷或在循环过程中发生在阴极颗粒中的裂解导致的。

If LFP does maintain an advantage in cycle life, rather than being completely superseded by LMFP as some people are speculating, it'll likely be around for a few more decades. That's because different use cases require different performance characteristics, and each battery chemistry has fundamental advantages that lends it to a specific use case. If you'd like to know more about that, watch my Battery Roadmaps video. As a side note, now that the chemistry issues appear to be solved for LMFP, companies like CATL are now faced with the next challenge for LMFP. Scaling it, it can take years to work the king set of new manufacturing processes, so that's how long it may take before we see LMFP batteries in wide use by the major EV producers like BYD and Tesla.

如果LFP确实在循环寿命方面具有优势，而不是像一些人猜测的那样被LMFP完全取代，它可能会在未来几十年继续存在。这是因为不同的用例需要不同的性能特征，每种电池化学成分都有固有优势，使其适用于特定的用例。如果您想了解更多信息，请观看我的《电池路线图》视频。另外，现在LMFP的化学问题似乎已经得到解决，像CATL这样的公司现在面临着LMFP的下一个挑战。扩展规模，可能需要几年的时间来制定一套新的制造流程，所以在我们看到像比亚迪和特斯拉这样的主要电动车制造商广泛使用LMFP电池之前可能需要一段时间。

As a final note, a big thanks to Battery Bulletin and Dr. Uho Heiska, who can be found on X. Battery Bulletin and Dr. Heiska helped me fill in the gaps for information that wasn't readily available in the literature. As always, any errors in the script are of course due to my own interpretation or communication errors. If you enjoyed this video, please consider supporting the channel by using the links in the description. Also consider following me on X. I often use X as a test bed for sharing ideas, and X subscribers like my Patreon supporters generally get access to my videos a week early. On that note, a special thanks to my YouTube members, X subscribers, and all the other patrons listed in the credits. I appreciate all of your support, and thanks for tuning in.

最后，特别感谢Battery Bulletin和Uho Heiska博士，在X上可以找到他。Battery Bulletin和Heiska博士帮助我填补了文献中没有提供的信息。正如这段视频中所述，脚本中的任何错误都是由于我自己的理解或沟通错误造成的。如果您喜欢这个视频，请考虑使用描述中的链接支持我的频道。同时考虑关注我在X上的账号。我经常在X上分享想法，X的订阅者，如我的Patreon支持者通常可以提前一周访问我的视频。在此，特别感谢我的YouTube会员，X的订阅者，以及名单中的所有其他赞助者。感谢大家的支持，谢谢收看。