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Dual-level engineering strategy shows promise for high-performance lithium–sulfur batteries

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Dual-level engineering strategy shows promise for high-performance lithium–sulfur batteries


Researchers develop a novel porous carbon nanofiber interlayer material with unsaturated cobalt single-atom catalysts. Credit: Seung-Keun Park and Inho Nam from Chung-Ang University Image source link: https://link.springer.com/article/10.1007/s42765-025-00614-w

Carbon-supported single-atom catalysts with metal-N moieties are highly promising for lithium–sulfur batteries. They can enhance redox kinetics and suppress the dissolution of lithium polysulfides. However, carbon substrate structure optimization and catalyst coordination environment modulation must be done simultaneously to maximize the potential of these catalysts.

Taking on this challenge, a team of researchers led by two associate professors from Chung-Ang University—Seung-Keun Park from the Department of Advanced Materials Engineering and Inho Nam from the Department of Chemical Engineering—has demonstrated dual‑level engineering of metal–organic framework (MOF)‑derived hierarchical porous carbon nanofibers with low‑coordinated cobalt single‑atom catalysts for high‑performance lithium–sulfur batteries. Their novel findings were published in Advanced Fiber Materials on 24 September 2025.

Dr. Park says, “Our motivation lies in addressing the fundamental materials challenges that have limited the development of next-generation energy storage systems. Lithium-ion batteries have been widely adopted but are approaching their intrinsic energy density limits.

“Lithium sulfur batteries offer much higher theoretical capacity and energy density, yet they are severely restricted by the polysulfide shuttle effect, slow redox kinetics, and rapid capacity fading. Our group has long been committed to overcoming these bottlenecks by combining structural engineering of carbon frameworks with atomic-level catalyst design.”

In this study, the researchers focused on embedding single cobalt atoms in a low-coordinated N3 environment within a porous carbon nanofiber network. This approach enhances the adsorption of lithium polysulfides and accelerates their redox reactions, thereby mitigating the shuttle effect and improving overall kinetics. Therefore, the present work supports the belief that rational materials design at both the macro and atomic levels can solve long-standing challenges.







Atomic trajectory of Co–N3 over representative segment of approximately 150 fs. Credit: Advanced Fiber Materials (2025). DOI: 10.1007/s42765-025-00614-w

From a materials perspective, the proposed dual-level engineering strategy integrates a hierarchical porous carbon nanofiber structure with atomically dispersed cobalt single-atom sites in a low-coordinated N3 configuration. The carbon nanofiber provides , abundant pore channels, and excellent electrolyte wettability, while the cobalt sites catalyze the adsorption and conversion of polysulfides. This synergistic design allows the battery to achieve high-capacity retention and superior rate performance over hundreds of cycles.

In the long term, the results of this study could contribute to the realization of high-performance lithium sulfur batteries for diverse real-life applications. These include with extended driving ranges, large-scale renewable energy storage systems that can balance intermittent solar and , and lightweight, flexible power sources for portable and wearable electronics.

“Our material is free standing, binder free, and flexible. It can be directly applied as an interlayer in pouch cells and has been demonstrated to maintain mechanical integrity even under bending, while powering small devices,” points out Dr. Nam, highlighting the immense practical implications of their work.

For society, such advances mean safer and more efficient batteries that accelerate the transition to clean energy. This can reduce dependence on critical raw materials, lower costs, decrease carbon emissions, and ultimately make sustainable technologies more reliable and accessible in everyday life.

More information:
Jeong Ho Na et al, Dual-Level Engineering of MOF-Derived Hierarchical Porous Carbon Nanofibers with Low-Coordinated Cobalt Single-Atom Catalysts for High-Performance Lithium–Sulfur Batteries, Advanced Fiber Materials (2025). DOI: 10.1007/s42765-025-00614-w

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OpenAI’s Child Exploitation Reports Increased Sharply This Year

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OpenAI’s Child Exploitation Reports Increased Sharply This Year


OpenAI sent 80 times as many child exploitation incident reports to the National Center for Missing & Exploited Children during the first half of 2025 as it did during a similar time period in 2024, according to a recent update from the company. The NCMEC’s CyberTipline is a Congressionally authorized clearinghouse for reporting child sexual abuse material (CSAM) and other forms of child exploitation.

Companies are required by law to report apparent child exploitation to the CyberTipline. When a company sends a report, NCMEC reviews it and then forwards it to the appropriate law enforcement agency for investigation.

Statistics related to NCMEC reports can be nuanced. Increased reports can sometimes indicate changes in a platform’s automated moderation, or the criteria it uses to decide whether a report is necessary, rather than necessarily indicating an increase in nefarious activity.

Additionally, the same piece of content can be the subject of multiple reports, and a single report can be about multiple pieces of content. Some platforms, including OpenAI, disclose the number of both the reports and the total pieces of content they were about for a more complete picture.

OpenAI spokesperson Gaby Raila said in a statement that the company made investments toward the end of 2024 “to increase [its] capacity to review and action reports in order to keep pace with current and future user growth.” Raila also said that the time frame corresponds to “the introduction of more product surfaces that allowed image uploads and the growing popularity of our products, which contributed to the increase in reports.” In August, Nick Turley, vice president and head of ChatGPT, announced that the app had four times the amount of weekly active users than it did the year before.

During the first half of 2025, the number of CyberTipline reports OpenAI sent was roughly the same as the amount of content OpenAI sent the reports about—75,027 compared to 74,559. In the first half of 2024, it sent 947 CyberTipline reports about 3,252 pieces of content. Both the number of reports and pieces of content the reports saw a marked increase between the two time periods.

Content, in this context, could mean multiple things. OpenAI has said that it reports all instances of CSAM, including uploads and requests, to NCMEC. Besides its ChatGPT app, which allows users to upload files—including images—and can generate text and images in response, OpenAI also offers access to its models via API access. The most recent NCMEC count wouldn’t include any reports related to video-generation app Sora, as its September release was after the time frame covered by the update.

The spike in reports follows a similar pattern to what NCMEC has observed at the CyberTipline more broadly with the rise of generative AI. The center’s analysis of all CyberTipline data found that reports involving generative AI saw a 1,325 percent increase between 2023 and 2024. NCMEC has not yet released 2025 data, and while other large AI labs like Google publish statistics about the NCMEC reports they’ve made, they don’t specify what percentage of those reports are AI-related.



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The Doomsday Glacier Is Getting Closer and Closer to Irreversible Collapse

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The Doomsday Glacier Is Getting Closer and Closer to Irreversible Collapse


Known as the “Doomsday Glacier,” the Thwaites Glacier in Antarctica is one of the most rapidly changing glaciers on Earth, and its future evolution is one of the biggest unknowns when it comes to predicting global sea level rise.

The eastern ice shelf of the Thwaites Glacier is supported at its northern end by a ridge of the ocean floor. However, over the past two decades, cracks in the upper reaches of the glacier have increased rapidly, weakening its structural stability. A new study by the International Thwaites Glacier Collaboration (ITGC) presents a detailed record of this gradual collapse process.

Researchers at the Centre for Earth Observation and Science at the University of Manitoba, Canada, analyzed observational data from 2002 to 2022 to track the formation and propagation of cracks in the ice shelf shear zone. They discovered that as the cracks grew, the connection between the ice shelf and the mid-ocean ridge weakened, accelerating the upstream flow of ice.

A fast-motion video of Thwaites Glacier in Antarctica over a period of about 10 years.

Video: University of Manitoba

The Crack in the Ice Shelf Widens in Two Stages

The study reveals that the weakening of the ice shelf occurred in four distinct phases, with crack growth occurring in two stages. In the first phase, long cracks appeared along the ice flow, gradually extending eastward. Some exceeded 8 km in length and spanned the entire shelf. In the second phase, numerous short cross-flow cracks, less than 2 km long, emerged, doubling the total length of the fissures.

Analysis of satellite images showed that the total length of the cracks increased from about 165 km in 2002 to approximately 336 km in 2021. Meanwhile, the average length of each crack decreased from 3.2 km to 1.5 km, with a notable increase in small cracks. These changes reflect a significant shift in the stress state of the ice shelf, that is, in the interaction of forces within its structure.

Between 2002 and 2006, the ice shelf accelerated as it was pulled by nearby fast-moving currents, generating compressive stress on the anchorage point, which initially stabilized the shelf. After 2007, the shear zone between the shelf and the Western ice tongue collapsed. The stress concentrated around the anchorage point, leading to the formation of large cracks.

Since 2017, these cracks have completely penetrated the ice shelf, severing the connection to the anchorage. According to researchers, this has accelerated the upstream flow of ice and turned the anchorage into a destabilizing factor.

Feedback Loop Collapse

One of the most significant findings of the study is the existence of a feedback loop: Cracks accelerate the flow of ice, and in turn, this increased speed generates new cracks. This process was clearly recorded by the GPS devices that the team deployed on the ice shelf between 2020 and 2022.

During the winter of 2020, the upward propagation of structural changes in the shear zone was particularly evident. These changes advanced at a rate of approximately 55 kilometers per year within the ice shelf, demonstrating that structural collapse in the shear zone directly impacts upstream ice flow.



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Grado’s Signature S750 Headphones Sound Modern but Feel Like the ’70s

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Grado’s Signature S750 Headphones Sound Modern but Feel Like the ’70s


The friction-pole mechanism for headband adjustment is no less agricultural, for all its familiarity where Grado headphone designs are concerned. And while the detachable cable is a fair bit more flexible than some older Grado models, that’s not the same as saying it’s meaningfully flexible. If there’s a more willfully unhelpful length of cable in all of headphone-land, I’ve yet to encounter it.

On the subject of the cable: Grado provides 180-ish centimeters of it with a 6.3-mm termination at the end. When you’re charging this sort of money for headphones, it’s not outlandish to imagine your customer might have a device that accepts a balanced connection. Frankly, why there isn’t a choice of cables in the packaging is, frankly, beyond me. It’s something that the overwhelming majority of Grado’s rivals provide as a matter of course, and though the company’s website suggests there are forthcoming cable options “including a variety of lengths, as well as balanced terminations such as 4-pin XLR and 4.4mm,” these have been “forthcoming” for quite some time now, and will have a cost attached.

Photograph: Simon Lucas

I’m in no position to doubt the effectiveness of the “B” ear cushions where sound quality is concerned. After all, the Signature S750 sound superb, and Grado suggests the cushion design is a contributing factor. What I do feel qualified to say, though, is that the raw-feeling foam of the ear cushions is not especially comfortable, and that it retains and returns the wearer’s body heat with something approaching glee. “Premium” and “luxurious” are not words that apply.

Ultimately, it depends on what your priorities are. There’s certainly no arguing with the way the Signature S750 sound. They’re uncomplicatedly impressive and periodically quite thrilling to listen to, depending on the mix. But unless you’re one of those hair-shirt hi-fi fundamentalists from back in the day, one of those listeners who somehow doesn’t believe outstanding sound quality is valid unless there’s some suffering attached, there may well be too many shortcomings to overlook when it comes to these Grados. “Hand-assembled in Brooklyn, USA” notwithstanding.



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