这项研究旨在通过引入铝（Al）和钨（W）作为单独或协同掺杂剂，优化无钴镍锰酸锂（Ni-rich, Co-free layered oxide materials）阴极材料的设计，以在不牺牲循环寿命的前提下提高能量密度。研究强调了化学成分和合成条件对材料颗粒形貌的影响，以及这种形貌如何决定电极的循环性能。除了常规材料表征，文章还分析了颗粒的机械强度，以深入理解材料在电极膨胀收缩过程中的表现，揭示了机械韧性在材料退化机制中的重要作用。最终开发出一种无钴阴极材料，在首次循环时容量可达260 mAh/g，在50次循环后仍保持95%的容量，在4.06V的截止电压下，循环100次容量无损。

💡 铝（Al）和钨（W）作为掺杂剂的引入，为设计高能量密度且长寿命的无钴镍锰酸锂阴极材料提供了新思路。研究发现，将它们作为单独或协同掺杂剂，能够有效提升材料的能量密度，同时保持优异的循环稳定性，这在以往被认为是难以实现的挑战。

🔬 材料的形貌对其循环性能至关重要，而形貌又受到化学成分和合成条件的影响。因此，深入理解这些因素之间的相互作用，对于优化阴极材料的设计具有决定性作用。研究人员通过多项表征手段，包括X射线衍射、扫描电子显微镜和增量容量分析等，来揭示这些关联。

💪 机械韧性是电池材料设计中常被忽视但至关重要的一环。研究特别关注了材料颗粒的强度测量，以更好地理解其在电极膨胀收缩过程中的行为。对于易产生微裂纹的材料而言，机械韧性信息是理解其退化机制的关键组成部分。

🚀 研究成功开发出一种无钴阴极材料，在4.3V的截止电压下，首次循环容量可达260 mAh/g，50次循环后容量保持率高达95%。而在较低的4.06V截止电压下，该材料可提供220 mAh/g的容量，且在100次循环后容量无明显衰减，显著提升了电池的能量密度和循环寿命。

In this work, Al and W are compared as individual dopants as well as co-dopants to arrive to an optimal cathode active material design. The objective is to improve the energy density of the materials without compromising cycle life; a feat which was previously thought unattainable for Ni-rich, Co-free layered oxide materials.

The findings emphasize the importance of understanding the effect of chemical composition and synthesis conditions on the morphology of the material particles. In turn, this morphology plays a determinant role in the cycling performance of the electrode.

In addition to conventional material characterization methods (such as x-ray diffraction, scanning electron microscopy, incremental capacity analysis, etc.), measurements of the particles’ strength were also analyzed to provide better insight on how the material will perform in an expanding-contracting electrode. Mechanical resilience if often overlook when studying and designing cathode materials, however, particularly in materials that are prone to microcracking, this information provides an important piece of the puzzle to understand the degradation mechanisms of the electrode.

This led to the development of a Co-free cathode material which can provide a capacity of 260 mAh/g on the first cycle while retaining 95% capacity after 50 cycles in half cells cycled to 4.3 V. At a lower upper-cutoff voltage of 4.06 V, this material delivers 220 mAh/g with no observable capacity loss after 100 cycles.

Ines Hamam has obtained her PhD in materials engineering (in 2024) and her MSc in physics (in 2020) from the University of Dalhousie under the supervision of world-renowned battery expert Dr Jeff Dahn. She is now a technologist at BMW furthering the world effort of transport electrification.

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