An Inexpensive High Energy Density And Long Cycle Life Halide Material Revealed
| Jerry Huang
Editor's note: In the field of energy storage, all-solid-state batteries are regarded as the best solution of next-generation energy storage technology, yet their development has long been constrained by critical bottlenecks in electrode materials. Traditional all-solid-state batteries (ASSBs) typically feature electrodes composed of active materials, solid electrolytes, and conductive additives. However, those inactive components (occupying 40–50% of electrodes volume) not only reduce energy density, but also induce interfacial side reactions and increase lithium-ion transport tortuosity. Although “All-In-One” designs (materials exhibiting high conductivity and electrochemical activity) could resolve these problems, existing materials like oxides (low capacity) and sulfides (high cost) struggle to meet requirements for future markets. Halides offer advantages in low cost and high ionic conductivity, yet suffer from insufficient electronic conductivity and energy density. Therefore, developing all-in-one materials that combine high electrochemical performance, inexpensive scalability with mechanical stability has become a critical challenge.
Here is an excellent example. A team from the University of Western Ontario in Canada provides a revolutionary answer in their Nature study—they designed the world's first halide material, Li₁.₃Fe₁.₂Cl₄, featuring dynamic self-healing capability and three-in-one integration (cathode/electrolyte/conductor). Through reversible Fe²⁺/Fe³⁺ redox reactions and a unique brittle-to-ductile transition mechanism, this material retains 90% capacity after 3,000 cycles, achieving an electrode energy density of 529.3 Wh kg⁻¹ (scalable to 725.6 Wh kg⁻¹ with composite designs). More remarkably, its cost is only 26% of conventional electrodes. Synchrotron radiation together with atomic simulations revealed an iron migration-induced self-healing mechanism for the first time! This work not only releases a core material for all-solid-state batteries but also provides a paradigm-level case for all-in-one design integrating materials, mechanics, and electrochemistry. Thanks to great efforts from all researchers.
Abstract
All-solid-state batteries require advanced cathode designs to realize their potential for high energy density and economic viability. Integrated all-in-one cathodes, which eliminate inactive conductive additives and heterogeneous interfaces, hold promise for substantial energy and stability gains but are hindered by materials lacking sufficient Li+/e− conductivity, mechanical robustness and structural stability. Here we present Li1.3Fe1.2Cl4, a cost-effective halide material that overcomes these challenges. Leveraging reversible Fe2+/Fe3+ redox and rapid Li+/e− transport within its framework, Li1.3Fe1.2Cl4 achieves an electrode energy density of 529.3 Wh kg−1 versus Li+/Li. Critically, Li1.3Fe1.2Cl4 shows unique dynamic properties during cycling, including reversible local Fe migration and a brittle-to-ductile transition that confers self-healing behaviour. This enables exceptional cycling stability, maintaining 90% capacity retention for 3,000 cycles at a rate of 5 C. Integration of Li1.3Fe1.2Cl4 with a nickel-rich layered oxide further increases the energy density to 725.6 Wh kg−1. By harnessing the advantageous dynamic mechanical and diffusion properties of all-in-one halides, this work establishes all-in-one halides as an avenue for energy-dense, durable cathodes in next-generation all-solid-state batteries.
References
https://doi.org/10.1038/s41586-025-09153-1