Yifei Mo

FPBench: A New Benchmark for Evaluating Foundation Potentials

2026-09-13T00:00:00+00:00

We introduce FPBench, an application-oriented benchmark for evaluating machine-learned foundation potentials (FPs) — models that promise to replace expensive first-principles calculations across atomistic simulations.

While FPs often report near-DFT accuracy on average energy and force errors, we found that these averages frequently fail to predict how a model actually performs on the tasks that matter in practice: force prediction for atomistic simulations, energy ranking of substitutional and vacancy orderings, and ion/vacancy migration.

FPBench introduces error-decomposition metrics that resolve force errors among highly accurate, large-error, and far-from-equilibrium atoms; relative-energy errors among competing orderings, phases, and compositions; and endpoint and along-path errors in ion migration — pinpointing exactly where and why a model breaks down, and providing targeted guidance for improving foundation potentials.

We have released an open benchmark, evaluation code, and a public leaderboard for the community to assess and compare foundation potentials.

Read the paper on arXiv, view the code, or explore the leaderboard.

New Oxyhalide Electrolyte Breaks Barriers for Solid-State Battery Performance

2025-10-09T00:00:00+00:00

A team led by Professor Yifei Mo, working with the University of Western Ontario and Oak Ridge National Laboratory, has developed a new class of oxyhalide solid electrolytes that combine fast lithium-ion transport with strong chemical stability — two properties that have historically been difficult to achieve in the same material.

The work, published in Science, reports a crystalline lithium oxyhalide electrolyte with a room-temperature ionic conductivity of 13.7 mS/cm, rivaling commercial liquid electrolytes, while remaining stable at cathode voltages up to 4.9 V and at temperatures as low as -50 °C.

Sulfide electrolytes conduct lithium ions well but are chemically unstable; oxides are stable but conduct poorly; halides fall in between. Mo’s group addressed this by mixing oxygen and chlorine anions within a single crystal lattice, combining the stability of oxides with the mechanical properties of halides while enabling the kind of favorable lithium-ion packing normally seen only in sulfides.

“By mixing the two, we can achieve the best of all chemistries.” — Yifei Mo

Batteries built with the new electrolyte sustained over 4,000 charge cycles with minimal capacity loss and, unlike sulfide electrolytes, showed good resistance to moisture — an advantage for manufacturing.

Read the full story at the UMD MSE news page.

Advanced Solid Electrolytes Break World Record for Ionic Conductivity

2024-10-31T00:00:00+00:00

A team led by Professor Yifei Mo, together with the Georgia Institute of Technology and Oak Ridge National Laboratory, has pushed the ionic conductivity of halide solid electrolytes to a new record by strategically tuning how anions move within the crystal lattice.

The work, published in Nature Chemistry, improved conductivity by more than two orders of magnitude over prior halide electrolytes, reaching room-temperature conductivities up to 11 mS/cm in mixed-anion variants — surpassing all previously reported values, and building on the halide solid electrolyte chemistry Panasonic introduced in 2018.

Combining synchrotron X-ray and neutron scattering with ab initio molecular dynamics simulations, the team found that collective anion motion drives the superionic transition responsible for fast ion transport. By tuning these anion dynamics, they lowered the transition temperature enough to achieve high conductivity at room temperature.

“This discovery provides a new pathway in the design of novel solid-state electrolytes.” — Yifei Mo

The result is a step toward practical, high-performance solid-state lithium-ion batteries for next-generation energy storage.

Read the full story at the UMD MSE news page.

New, Superfast Method for Ceramic Manufacturing Could Open Door to AI-Driven Materials Discovery

2020-04-30T00:00:00+00:00

Conventional ceramic sintering — the firing step that hardens ceramic materials — typically takes hours, a bottleneck for developing new solid-electrolyte and other functional ceramics. A UMD team led by Professor Liangbing Hu reinvented the process into an ultrafast high-temperature sintering method, sandwiching a pressed ceramic pellet between carbon strips that heat it by radiation and conduction to temperatures up to 3,000°C in under 10 seconds — over 1,000 times faster than a traditional furnace.

Professor Yifei Mo collaborated on the study, published on the cover of Science, which also involved Bao Yang, J.C. Zhao, and Howard Wang at UMD along with researchers at UC San Diego and UCLA.

“This new method solves the key bottleneck problem in computation and AI-guided materials discovery.” — Yifei Mo

By collapsing sintering time from tens of hours to seconds, the technique clears a path for rapidly synthesizing and testing the large numbers of candidate materials that computational and AI-driven materials discovery can generate — with applications spanning solid-state batteries, fuel cells, and 3D-printed ceramics. The technology is being commercialized through the UMD spinoff HighT-Tech LLC.

“A general method to synthesize and sinter bulk ceramics in seconds” appears in Science, 368, 521-526 (2020) (DOI: 10.1126/science.aaz7681).

Read the full story at the UMD MSE news page.

The Battery Revolution

2019-07-10T00:00:00+00:00

Fires in phones, laptops, and even a jumbo jet share a common cause: the flammable liquid electrolyte inside conventional lithium-ion batteries. Alongside their fire risk, these batteries also fall short on charging speed and energy density — driving researchers to look for a safer, better alternative.

Professor Yifei Mo’s group uses supercomputers paired with machine learning to model battery materials atom by atom, predicting how they conduct lithium ions and speeding up the search for viable solid-state battery materials.

“What we’re after is ultimate safety, energy density, life cycle, and charging time.” — Yifei Mo

Fast lithium-ion diffusion in solids is rare, and only a handful of materials achieve it at room temperature. By training machine learning models on existing materials data, Mo’s lab — among the first to apply ML to this problem — has helped uncover promising new candidates, filing multiple patents and working with industry partners to bring the technology toward commercialization.

Read the full story at the UMD MSE news page.

Mo Research Group’s Solid-State Battery Review Published in Joule

2018-09-24T00:00:00+00:00

All-solid-state batteries promise higher energy density and safety than today’s liquid-electrolyte lithium-ion batteries, but progress is limited by a scarcity of fast Li-ion-conducting ceramics and unstable solid-solid interfaces. Computational materials modeling offers a way to probe these problems directly, down to the femtosecond dynamics of individual atoms.

Invited by Joule, Professor Yifei Mo’s group — led by first author and Ph.D. student Adelaide Nolan, with Yizhou Zhu, Xingfeng He, and Qiang Bai — reviewed the state of the art in computational modeling of materials and interfaces for all-solid-state Li-ion batteries.

“With computation, we can directly observe the diffusion mechanisms of lithium ions.” — Adelaide Nolan

The review traces how first-principles computation, requiring no empirical input, has both explained why certain solids conduct lithium ions quickly and guided the discovery of new solid electrolyte materials — work Mo’s group continues to pursue with industry partners toward commercialization.

“Computation-Accelerated Design of Materials and Interfaces for All-Solid-State Lithium-Ion Batteries” appears in Joule (DOI: 10.1016/j.joule.2018.08.017).

Read the full story at the UMD MSE news page.

MSE Researchers Discover New Materials, New Research Direction for High-energy Li-metal Batteries

2017-04-20T00:00:00+00:00

Lithium metal packs lithium atoms far more densely than conventional graphite anodes, making it the most attractive anode material for high-energy batteries — but its strongly reducing nature degrades most electrolytes over time, causing rapid capacity fade.

Professor Yifei Mo, with Ph.D. students Yizhou Zhu and Xingfeng He, ran quantum mechanical calculations across a large-scale materials database to screen for materials that stay stable against lithium metal. Unlike the oxides, sulfides, and halides typically used to protect lithium anodes, nitrides turned out to have a natural, thermodynamically intrinsic resistance to reduction by lithium.

“We discovered that nitrides exhibit unique thermodynamically intrinsic stability.” — Yifei Mo

The finding points to a new research direction: using nitride materials and nitrogen doping to stabilize lithium metal anodes, a step toward higher-energy rechargeable batteries for applications like long-range electric vehicles.

The work, “Strategies Based on Nitride Materials Chemistry to Stabilize Li Metal Anode,” is published in Advanced Science (DOI: 10.1002/advs.201600517).

Read the full story at the UMD MSE news page.

MSE Researchers Publish Series Study on All-Solid-State Batteries

2016-10-28T00:00:00+00:00

Commercial lithium-ion batteries rely on flammable organic liquid electrolytes — a safety weak point behind several high-profile battery-fire incidents. Replacing them with non-flammable ceramic solid electrolytes could make all-solid-state Li-ion batteries intrinsically safer, with higher energy density, faster charging, and longer cycle life. A major obstacle, though, is the poorly understood, high resistance at the interfaces between solid components.

Using quantum mechanical modeling on UMD’s Deepthought2 supercomputer, Professor Yifei Mo’s group studied these elusive interfaces and proposed strategies to improve them, publishing a series of papers — one featured on the cover of the Journal of Materials Chemistry A — with collaborators including Chunsheng Wang and graduate students Yizhou Zhu, Fudong Han, and Xingfeng He.

Papers in the series:

“First Principles Study on Electrochemical and Chemical Stability of the Solid Electrolyte-Electrode Interfaces in All-Solid-State Li-ion Batteries,” Journal of Materials Chemistry A, 4, 3253-3266 (2016) — cover feature
“Electrochemical Stability of Li10GeP2S12 and Li7La3Zr2O12 Solid Electrolytes,” Advanced Energy Materials, 6, 1501590 (2016)
“Origin of Outstanding Stability in the Lithium Solid Electrolyte Materials: Insights from Thermodynamic Analyses Based on First-Principles Calculations,” ACS Applied Materials & Interfaces, 7, 23685-23693 (2015)

Read the full story at the UMD MSE news page.