In the relentless pursuit of enhancing lithium-ion battery performance and longevity, researchers have confronted a persistent challenge residing within layered oxide cathodes: a structural phenomenon known as lattice collapse. Specifically, in high-nickel layered oxides like LiNi_0.9Mn_0.1O_2, the cathode undergoes significant dimensional changes during battery operation, notably a sudden shrinkage along the crystallographic c-axis—termed “c-collapse”—when charged to high voltages. This abrupt contraction induces mechanical strain that propagates microstructural damage and ultimately curtails the battery’s usable life. However, a novel breakthrough from an international team of scientists now reveals a method to eliminate this destructive lattice collapse without resorting to complex doping strategies, opening a promising avenue for durable, high-capacity energy storage.
The team’s innovative approach involves inducing partial disordering within the cation sublattice of the LiNi_0.9Mn_0.1O_2 cathode through an electrochemical technique that leverages a key feature of Li-excess, nickel-rich oxides—namely, the irreversible oxidation of oxygen ions. Unlike typical compositional modifications where dopants are introduced to stabilize the crystal structure, their method utilizes controlled charging protocols to initiate intrinsic structural rearrangements. These rearrangements produce a stable, partially disordered distribution of transition-metal ions occupying lithium lattice sites (TM_Li), permanently altering the bulk cathode’s internal architecture.
The genesis of this disorder is a subtle but critical phenomenon. During electrochemical cycling, once the oxygen ions undergo irreversible oxidation, the lattice gains additional redox activity that drives transition-metal ions to migrate into lithium positions, creating cation mixing. Remarkably, this phenomenon, which was traditionally viewed as detrimental, is harnessed here to arrest the harmful c-collapse. By varying the initial lithium excess in the material, the researchers precisely tune the level of partial disorder induced, enabling them to systematically engineer the bulk cathode composition from lithium-excess to nominally stoichiometric transition-metal oxides with controlled cation disorder.
One of the most striking findings of this study is the discovery that when the concentration of transition-metal ions residing on lithium sites reaches or surpasses approximately 12%, the cathode’s c-lattice parameter ceases to contract notably during charging and discharging cycles. This near-invariance of the c-axis lattice spacing dramatically reduces the chemical strain that would otherwise accumulate within the lattice framework. Such strain mitigation translates into the preservation of the cathode’s microstructural integrity over extended cycling, addressing a fundamental bottleneck facing current high-nickel cathode materials.
In traditional layered oxides, the lattice contraction at high states of charge triggers phase transitions and structural instabilities. These mechanisms foment the formation of microcracks and pulverization of cathode particles, which progressively degrade electrochemical performance. The current work’s strategy sidesteps these pitfalls entirely by preemptively stabilizing the lattice through intrinsic cation disorder rather than imposing external dopants. This intrinsic architectural modulation represents a paradigm shift, highlighting the potential for electrochemical activation as a tool to design cathode materials with self-stabilizing properties.
Notably, the partially disordered cathodes retain a long-range layered crystal structure despite the cation mixing, preserving the essential pathways for lithium-ion migration. This structural integrity underpins the observed benefits in electrochemical performance: the materials deliver high specific capacities consistent with Ni-rich oxides, but with substantially enhanced cycling stability and dramatically reduced voltage hysteresis. Furthermore, the negligible voltage decay over extensive cycling is a strong indicator of long-term operational stability—a prized feature for commercial battery applications.
The implications for battery technology are profound. High-nickel layered oxides are prized for their high energy density but are notorious for their stability issues under real-world operating conditions. Achieving a stable lattice without introducing foreign dopants simplifies material synthesis and lowers costs, while the demonstrated ability to tune cation disorder promotes customizable performance. This electrochemical engineering approach can be integrated into existing manufacturing workflows, potentially accelerating the commercialization of robust, long-life lithium-ion batteries based on Ni-rich cathodes.
Mechanistically, the team provided comprehensive structural analysis corroborating the electrochemically induced phase changes. Advanced synchrotron X-ray diffraction and transmission electron microscopy revealed that the bulk cathode maintains coherent layered domains even as cation disorder is induced. This insight clarifies why lithium diffusion kinetics remain favorable, and the preservation of layered ordering maintains high-rate capabilities. These findings challenge conventional wisdom that disorder necessarily compromises electrochemical performance, instead demonstrating that a controlled degree of disorder can be beneficial.
Beyond the immediate material studied, this discovery opens the door to leveraging electrochemical pathways to induce persistent intrinsic disorder in other cathode chemistries. The interplay between oxygen redox activity and cation rearrangement offers a rich landscape for future materials innovation. Researchers may explore how varying lithium excess, cycling protocols, and external parameters can be balanced to optimize performance in other layered oxides, potentially leading to a new generation of smart, self-adapting electrodes.
From a practical perspective, the extended cycle life gained by suppressing lattice collapse directly addresses one of the lithium-ion battery market’s most critical challenges: degradation under high-voltage operation. Enhanced stability mitigates capacity fade, voltage hysteresis, and safety concerns stemming from structural failure. In electric vehicles, portable electronics, and grid storage systems, such improvements translate to longer run times, fewer replacements, and reduced environmental impact.
As the field advances toward the next milestones in battery technology, this research stands out as a compelling example of transformative materials design through electrochemical manipulation. The absence of dopants reduces compositional complexity and potential side reactions, while the retention of a robust layered framework ensures that the cathode remains an efficient lithium host over many cycles. This elegant solution to lattice collapse demonstrates how fundamental understanding of redox chemistry and lattice dynamics can inspire practical innovation.
In conclusion, the work by Lee, Jiang, Liang, and colleagues marks a watershed moment in cathode material engineering. By exploiting the irreversible oxygen oxidation-induced cation disorder, they have fundamentally altered the structural evolution of LiNi_0.9Mn_0.1O_2 cathodes, circumventing the fatal c-axis lattice collapse that has long limited battery longevity. Their discovery provides a blueprint for new design principles where electrochemical stimuli trigger self-stabilizing structural transformations, marrying high energy density with exceptional durability. As electric vehicles and renewable energy systems demand ever more reliable battery solutions, such breakthroughs will be pivotal in powering a sustainable future.
Subject of Research: Suppression of lattice collapse in Ni-rich layered oxide cathodes for lithium-ion batteries by electrochemically induced partial cation disorder.
Article Title: Eliminating lattice collapse in dopant-free LiNi_0.9Mn_0.1O_2 cathodes via electrochemically induced partial cation disorder.
Article References:
Lee, J., Jiang, Z., Liang, N.B. et al. Eliminating lattice collapse in dopant-free LiNi_0.9Mn_0.1O_2 cathodes via electrochemically induced partial cation disorder. Nat Energy (2025). https://doi.org/10.1038/s41560-025-01910-w
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