Novel regeneration strategy restores high-nickel lithium-ion battery cathodes for enhanced performance and sustainability

Maximum Academic Press

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This new direct regeneration approach, employing a LiOH-LiNiO3-lithium salicylate (LSA) eutectic salt system, restores the structural integrity and electrochemical performance of spent cathodes, offering a promising solution to enhance the lifespan and sustainability of lithium-ion batteries (LIBs).

LIBs are integral to modern energy storage, particularly in electric vehicles (EVs), due to their high energy density and long lifespan. However, the average lifespan of LIBs is about 5–8 years, with millions of tons of retired batteries expected by 2030. These spent batteries contain valuable materials like lithium, nickel, and cobalt, which are critical for resource recovery. Traditional recycling methods, such as pyrometallurgy and hydrometallurgy, face challenges like high energy consumption, environmental pollution, and the loss of material structure. In contrast, direct regeneration restores cathode materials by repairing their structure and compensating for lithium loss, making it a more sustainable and efficient recycling solution. However, previous regeneration methods for high-nickel NCM811 cathodes have struggled with uneven lithium compensation and structural degradation.

A study (DOI:10.48130/een-0025-0004) published in Energy & Environment Nexus on 16 October 2025 by Yang Yang’s team, Huazhong University of Science and Technology, not only extends the lifespan of the material but also improves its energy density, making it suitable for reuse in new batteries.

To investigate the structural evolution of spent NCM811 cathodes during degradation and regeneration, X-ray diffraction (XRD) and inductively coupled plasma optical emission spectrometry (ICP-OES) were employed. XRD analysis revealed that the regenerated R-NCM811 exhibited a well-ordered layered structure, with clear diffraction peaks at the (003), (101), and (104) planes. In contrast, the degraded S-NCM811 showed weaker, broadened diffraction peaks and a NiO impurity phase, indicating significant structural degradation. ICP-OES results showed that S-NCM811 had a lower lithium-to-metal ratio, reflecting lithium loss, while R-NCM811 demonstrated effective lithium compensation, with a higher Li/(Ni+Co+Mn) ratio, confirming structural integrity restoration. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) images showed that S-NCM811 particles were fragmented and cracked due to lattice distortion, whereas R-NCM811 exhibited smoother particles with more uniform sizes, indicating effective ion exchange and phase reconstruction. The regeneration process successfully healed microcracks and transformed polycrystalline materials into single crystals. Electrochemical testing revealed that R-NCM811 had a significantly higher initial discharge capacity (196.0 mAh·g–1) compared to S-NCM811 (105.7 mAh·g–1). After 200 cycles, R-NCM811 retained 76.0% of its capacity, indicating improved cycling stability. Cyclic voltammetry (CV) and impedance spectroscopy further confirmed the enhanced lithium-ion diffusion and interface reaction kinetics in the regenerated material. The successful regeneration was attributed to the synergistic effect of the LSA eutectic salt system, which facilitated lithium compensation, eliminated the NiO rock salt phase, and improved the material's crystallinity, restoring its electrochemical performance and structural integrity.

This study presents a promising approach for the regeneration of high-nickel NCM811 cathodes, overcoming critical issues related to lithium loss, structural degradation, and performance decline in spent materials. The use of a LiOH-LiNiO3-LSA eutectic salt system offers an efficient, sustainable solution to restore cathode materials, providing new opportunities for closed-loop recycling and the development of long-lasting, high-performance batteries. As this method advances towards industrial scale-up, it could play a pivotal role in meeting the growing demand for energy storage and reducing the environmental impact of spent batteries.

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References

DOI

10.48130/een-0025-0004

Original Source URL

https://doi.org/10.48130/een-0025-0004

Funding information

The authors acknowledge research project 52576210 supported by National Natural Science Foundation of China.

About Energy & Environment Nexus

Energy & Environment Nexus is a multidisciplinary journal for communicating advances in the science, technology and engineering of energy, environment and their Nexus.

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DOI

10.48130/een-0025-0004 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Molten salt regeneration of single-crystal LiNi0.8Co0.1Mn0.1O2 from end-of-life cathodes

 

Delayed climate mitigation could trigger a socioeconomic tipping point

Maximum Academic Press

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Using an integrated assessment model, the research finds that the social cost of carbon (SCC)—a key indicator guiding climate action—may rise with warming at first but then sharply decline once damages exceed a critical threshold. Such a decline would weaken global motivation to deploy renewable energy and could accelerate warming far beyond temperature goals.

Global temperatures are approaching 1.5 °C above pre-industrial levels, with projections indicating a high likelihood of surpassing 2 °C this century. Despite clear scientific warnings, global CO₂ emissions have rebounded following the COVID-19 pandemic due to stimulated consumption, fossil-fuel-locked infrastructure, and slow deployment of renewable energy. Economic inertia, workforce barriers, stranded fossil fuel assets, and inconsistent mitigation policies further hinder progress. Many countries continue to adopt a “wait-and-see” strategy based on the assumption that the SCC—and therefore the incentive for mitigation—will naturally increase as climate damages worsen. Based on these challenges, there is an urgent need to test whether delayed action may instead erode the incentive to mitigate.

A study (DOI:10.48130/een-0025-0012) published in Energy & Environment Nexus on 28 October 2025 by Rong Wang, Fudan University, highlights that waiting for climate damages to intensify before acting may undermine the very incentives needed to reduce fossil fuel use.

The study introduces a modified cost–benefit integrated assessment model designed to optimize long-term choices in consumption, labor, and investment while governing the pace of transition from fossil fuels to renewable energy. Using a CES production function calibrated with historical data, the model incorporates realistic elasticities between energy and nonenergy inputs, varying substitution possibilities between fossil and renewable energy, and empirically grounded learning rates that reflect past declines in renewable energy costs. An empirical climate-damage function further links rising temperatures to economic losses, with parameters aligned to recent evidence and the Paris Agreement’s temperature thresholds. Mitigation is triggered in different years by sharply reducing the pure rate of time preference, and 10,000 Monte Carlo simulations evaluate uncertainties across key factors such as technological progress, climate system response times, and the capacity of backstop technologies. The results reveal that mitigation costs grow steeply at deep decarbonization levels: a 50% reduction in fossil fuel supply lowers GDP by only about 5%–8%, whereas a 90% reduction can reduce GDP by 21%–51%, highlighting stringent technological and geophysical limits. The model also projects substantially higher damages at 2 °C warming—around 20%–50% of global GDP—than classic DICE-type models, better matching empirical assessments. If mitigation begins by 2025, renewable energy could reach roughly 90% of total supply by 2100, holding climate damages near 10% of GDP. In contrast, delaying action until after 2050 results in sluggish renewable deployment, damages nearing 30% of GDP, and a rapid decline in the social cost of carbon—often below USD 1,000/tCO₂—reducing the likelihood of limiting warming to 2 °C to under 10%. Sensitivity tests confirm that this pattern of initially rising but ultimately collapsing mitigation incentives is robust. Moreover, consistently low renewable energy shares once damages exceed about 10% of GDP may signal an approaching socioeconomic tipping point.

The study shows that waiting for rising climate damages will not strengthen mitigation incentives; instead, delaying action can weaken renewable energy adoption and entrench fossil fuel dependence. By revealing how a declining SCC aligns with slowing energy transitions, the research calls for an early-warning mechanism in the Global Stocktake to track climate damages and renewable energy shares. Such monitoring could signal when a socioeconomic tipping point is approaching, enabling timely policy intervention to avoid irreversible temperature overshoot.

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References

DOI

10.48130/een-0025-0012

Original Source URL

https://doi.org/10.48130/een-0025-0012

About Energy & Environment Nexus

Energy & Environment Nexus is a multidisciplinary journal for communicating advances in the science, technology and engineering of energy, environment and their Nexus.

---

DOI

10.48130/een-0025-0012 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

A slower-than-needed scale-up of renewable energy might reduce the incentive for mitigation

 

LLMs choose friends and colleagues like people

PNAS Nexus

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image: 

Networks generated by LLM agents exhibiting “preferential attachment” (panel A), “triadic closure” (panel B), “homophily” (panel C), and “small-world” dynamics (panel D).

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Credit: Marios Papachristou and Yuan Yuan

When large language models (LLMs) make decisions about networking and friendship, the models tend to act like people, across both synthetic simulations and real-world network contexts. Marios Papachristou and Yuan Yuan developed a framework to study network formation behaviors of multiple LLM agents and compared these behaviors against human behaviors. The authors conducted simulations using several large language models placed in a network, which were asked to choose which other nodes to connect with, given their number of connections, common neighbors, and shared attributes, like arbitrarily assigned “hobbies” or “location.” The authors varied the network context, including simulations of friendships and workplace, communities; the amount of information provided to the agents; and model parameters like temperature. Generally, LLMs exhibited tendencies to connect to other nodes that were already well connected, a phenomenon called “preferential attachment.” LLMs also showed a tendency to connect to other nodes with a high number of common connections, a phenomenon called “triadic closure.” LLMs also demonstrated homophily, choosing nodes with similar hobbies or location, as well as the “small-world” phenomenon, where any two nodes are connected by surprisingly short chains of acquaintances often with just a few “degrees of separation.” In network simulations based on real Facebook friendship networks, work networks, and telecommunication networks, LLM models prioritized homophily most strongly, followed by triadic closure and preferential attachment. Finally, the authors conducted a controlled survey with around 100 human participants and asked participants and to respond to the same survey. LLMs' responses showed strong alignment with human link-formation choices, though the models displayed higher internal consistency than humans. According to the authors, these findings demonstrate the potential for LLMs to be used as a source of synthetic data when privacy concerns preclude using human data, but also raise questions regarding the design and alignment of artificial intelligence systems that make real-world decisions by interacting with human networks.

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Journal

PNAS Nexus

Article Title

Network formation and dynamics among multi-LLMs

Article Publication Date

2-Dec-2025

 

Gas stoves and nitrogen dioxide exposure

PNAS Nexus

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image: 

Indoor (gold) and outdoor (blue) average nitrogen dioxide exposures.

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Credit: Kashtan et al.

Twenty-two million Americans would no longer be breathing in unhealthy levels of nitrogen dioxide if they switched from gas and propane stoves to electric stoves. Robert Jackson and colleagues combined outdoor air quality data with estimates of indoor nitrogen dioxide emissions from stoves in more than fifteen cities. As outdoor air quality improves, stoves become an increasingly important source of exposure. According to the World Health Organization, health risks to the respiratory system increase at levels above 5.2 parts per billion by volume. Taking indoor and outdoor sources together, the authors found that average total residential long-term nitrogen dioxide exposure is approximately 10 parts per billion by volume for people with gas stoves and approximately 8 parts per billion by volume for those with electric stoves. For households in the 95th percentile of gas stove use, which corresponds to using multiple gas burners and a gas oven for multiple hours a day, stoves account for more than half of total nitrogen dioxide exposure. The authors estimate that approximately 22 million people whose outdoor nitrogen dioxide exposure falls below World Health Organization guidelines exceed those guidelines due to gas stove use. According to the authors, the study’s ZIP-code-level exposure maps could help identify regions to prioritize for indoor and outdoor air quality interventions, particularly in lower-income communities.

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Journal

PNAS Nexus

Article Title

Integrating indoor and outdoor nitrogen dioxide exposures in US homes nationally by ZIP code

Article Publication Date

2-Dec-2025