Tech
Scandium doping technique extends sodium-ion battery life
Because lithium is relatively scarce and sodium is abundant in Earth’s crust, sodium-ion batteries are being investigated as viable, cost-effective alternatives to the widely used lithium-ion batteries. In these batteries, the choice of cathode material primarily influences battery capacity and stability.
Layered sodium manganese oxides (Na2/3MnO2) have attracted significant attention in recent years as cathode materials for high-capacity sodium-ion batteries without using any rare-earth metals. However, while these materials exhibit high initial capacity, their rapid capacity fading during charge-discharge cycling remains a significant challenge.
During charge-discharge cycling of NaMnO2 electrodes, Na+ ions are constantly inserted and extracted from the cathode material. This is accompanied by changes in the oxidation states of manganese (Mn) between Mn3+ to Mn4+. When Mn3+ ions form, they distort their surrounding lattice to lower electronic energy, a phenomenon known as Jahn-Teller distortion.
Over time, these repeated distortions lead to a buildup of strain at both atomic and particle levels in NaMnO2, eventually resulting in the loss of crystallinity and severe capacity degradation. This is the main cause of capacity loss during cycling of Na2/3MnO2 electrodes. Recent studies have attempted to address this issue by substituting metals at Mn sites.
In a recent study, a research team led by Professor Shinichi Komaba, along with Mr. Kodai Moriya and Project Scientist Dr. Shinichi Kumakura, from the Department of Applied Chemistry at Tokyo University of Science, Japan, revealed how scandium (Sc) doping can dramatically improve the cycling stability of P’2 polytype of Na2/3MnO2 electrodes.
“Previously, we discovered that Sc doping in P’2 Na2/3[Mn1-xScx]O2 electrodes can improve the battery performance and long-term stability,” explains Prof. Komaba. “However, the exact mechanism for this improvement remains unresolved, and it was unclear whether this effect is generally applicable. In this study, we systematically studied P2 and P’2 polytypes of Na2/3[Mn1-xScx]O2 to understand the role of Sc doping.”
Their study was published in the journal Advanced Materials on September 12, 2025.
The crystal structure of Na2/3MnO2 has several polytypes, which differ in several aspects. A key difference between the P2 and P’2 polytypes is that former exhibits localized Jahn-Teller distortions, while the latter features cooperative Jahn-Teller distortion where the distortions are aligned in a long-range order. The researchers conducted a series of experiments on both doped and undoped samples of each polytype containing varying amounts of Sc.
Structural tests revealed that Sc doping in P’2 Na2/3[Mn1-xScx]O2 effectively modulates its structure, resulting in smaller particles and altered crystal growth, while preserving cooperative Jahn-Teller distortion and superstructure. This significantly improves structural stability. In addition, the team found that Sc doping prevents side reactions with liquid electrolytes and enhances moisture stability by forming a cathode-electrolyte interface layer.
As a result, in Na-half-cell tests, the Sc-doped P’2 type Na2/3[Mn1-xScx]O2 electrodes demonstrated a substantial improvement in cycling stability. The sample with 8% Sc doping was found to have optimal performance.
The researchers also found that unlike non-doped samples, the crystallinity of the doped samples was remarkably maintained during cycling. Interestingly, Sc doping did not improve the cycling stability of P2 NaMnO2 electrodes, indicating a specific synergy between Sc doping and cooperative Jahn-Teller distortion. Furthermore, doping with other similar metal cations, like ytterbium and aluminum, did not reduce capacity fading, highlighting the unique role of Sc.
They also tested the effect of pre-cycling, a common technique to improve cycle life, which further improved capacity retention in the doped P’2 Na2/3[Mn1-xScx]O2 electrodes. Building upon these results, the researchers fabricated coin-type full cells using the 8% Sc-doped P’2 Na2/3[Mn1-xScx]O2 electrodes, which demonstrated an impressive 60% capacity retention after 300 cycles.
“Since Sc is an expensive metal, our study demonstrates its feasibility in the development of batteries. Our findings can potentially lead to development of high-performance and long-life sodium-ion batteries,” says Prof. Komaba, highlighting the importance of their research.
“Moreover, beyond sodium-ion batteries, our study illustrates a new strategy to extend the structural stability of layered metal oxides involving the lattice distortion and improve the performance of batteries made using these materials.”
Overall, this study demonstrates the unique role of Sc doping for improving cycling stability of sodium-ion batteries, paving the way for their broader adoption.
More information:
Kodai Moriya et al, Unique Impacts of Scandium Doping on Electrode Performance of P’2‐ and P2‐type Na2/3MnO2, Advanced Materials (2025). DOI: 10.1002/adma.202511719
Citation:
Scandium doping technique extends sodium-ion battery life (2025, September 17)
retrieved 17 September 2025
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Over the weekend, the Justice Department released three new data sets comprising files related to Jeffrey Epstein. The DOJ had previously released nearly 4,000 documents prior to the Friday midnight deadline required by the Epstein Files Transparency Act.
As with Friday’s release, the new tranche appears to contain hundreds of photographs, along with various court records pertaining to Epstein and his associates. The first of the additional datasets, Data Set 5, is photos of hard drives and physical folders, as well as chain-of-custody forms. Data Set 6 appears to mostly be grand jury materials from cases out of the Southern District of New York against Epstein and his coconspirator, Ghislaine Maxwell. Data Set 7 includes more grand jury materials from those cases, as well as materials from a separate 2007 Florida grand jury.
Data Set 7 also includes an out-of-order transcript between R. Alexander Acosta and the DOJ’s Office of Professional Responsibility from 2019. According to the transcript, the OPR was investigating whether attorneys in the Southern District of Florida US Attorney’s Office committed professional misconduct by entering into a non-prosecution agreement with Epstein, who was being investigated by state law enforcement on sexual battery charges. Acosta was the head of the office when the agreement was signed.
Leading up to the deadline to release materials, the DOJ made three separate requests to unseal grand jury materials. Those requests were granted earlier this month.
The initial release of the Epstein files was met with protest, particularly by Epstein victims and Democratic lawmakers. “The public received a fraction of the files, and what we received was riddled with abnormal and extreme redactions with no explanation,” wrote a group of 19 women who had survived abuse from Epstein and Maxwell in a statement posted on social media. Senator Chuck Schumer said Monday that he would force a vote that would allow the Senate to sue the Trump administration for a full release of the Epstein files.
Along with the release of the new batch of files over the weekend, the Justice Department also removed at least 16 files from its initial offering, including a photograph that depicted Donald Trump. The DOJ later restored that photograph, saying in a statement on X that it had initially been flagged “for potential further action to protect victims.” The post went on to say that “after the review, it was determined there is no evidence that any Epstein victims are depicted in the photograph, and it has been reposted without any alteration or redaction.”
The Justice Department acknowledged in a fact sheet on Sunday that it has “hundreds of thousands of pages of material to release,” claiming that it has more than 200 lawyers reviewing files prior to release.
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.
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.
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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