An official website of the United States government
Amidst the rapid expansion of the electric vehicle industry, the need for alternative battery technologies that balance economic viability with sustainability has never been more critical. Here, we report that common lithium salts of Li2CO3 and Li2SO4 are transformed into cathode active mass in Li-ion batteries by ball milling to form a composite with Cu2S. The optimal composite cathode comprising Li2CO3, Li2SO4, and Cu2S, with a practical active mass loading of 12.5-13.0 mg/cm2, demonstrates a reversible capacity of 247 mAh/g based on the total mass of Cu2S and the lithium salts, a specific energy of 716 Wh/kg, and a stable cycle life. This cathode chemistry rivals layered oxide cathodes of Li-ion batteries in energy density but at substantially reduced cost and ecological footprint. Mechanistic investigations reveal that in the composite Li2CO3 serves as the primary active mass, Li2SO4 enhances kinetic properties and reversibility, and Cu2S stabilizes the resulting anionic radicals for reversibility as a binding agent. Our findings pave the way for directly using precursor lithium salts as cathodes for Li-ion batteries to meet the ever-increasing market demands sustainably.
more »
« less
Solvent-mediated oxide hydrogenation in layered cathodes
Self-discharge and chemically induced mechanical effects degrade calendar and cycle life in intercalation-based electrochromic and electrochemical energy storage devices. In rechargeable lithium-ion batteries, self-discharge in cathodes causes voltage and capacity loss over time. The prevailing self-discharge model centers on the diffusion of lithium ions from the electrolyte into the cathode. We demonstrate an alternative pathway, where hydrogenation of layered transition metal oxide cathodes induces self-discharge through hydrogen transfer from carbonate solvents to delithiated oxides. In self-discharged cathodes, we further observe opposing proton and lithium ion concentration gradients, which contribute to chemical and structural heterogeneities within delithiated cathodes, accelerating degradation. Hydrogenation occurring in delithiated cathodes may affect the chemo-mechanical coupling of layered cathodes as well as the calendar life of lithium-ion batteries.
more »
« less
- PAR ID:
- 10614190
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- AAAS
- Date Published:
- Journal Name:
- Science
- Volume:
- 385
- Issue:
- 6714
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 1230 to 1236
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
The growing interest in sodium-ion batteries (SIBs) is driven by scarcity and the rising costs of lithium, coupled with the urgent need for scalable and sustainable energy storage solutions. Among various cathode materials, layered transition metal oxides have emerged as promising candidates due to their structural similarity to lithium-ion battery (LIB) counterparts and their potential to deliver high energy density at reduced costs. However, significant challenges remain, including limited capacity at high charge/discharge rates and structural instability during extended cycling. Addressing these issues is critical for advancing SIB technology toward industrial applications, particularly for large-scale energy storage systems. This review provides a comprehensive analysis of layered sodium transition metal oxides, focusing on their structural properties, electrochemical performance, and degradation mechanisms. Special attention is given to the intrinsic and extrinsic factors contributing to their instability, such as structural phase transitions, and cationic/anionic redox behavior. Additionally, recent advancements in material design strategies, including doping, surface modifications, and composite formation, are discussed to highlight the progress toward enhancing the stability and performance of these materials. This work aims to bridge the knowledge gaps and inspire further innovations in the development of high-performance cathodes for sodium-ion batteries.more » « less
-
Reusing valuable cathode materials from end-of-life (EOL) Li-ion batteries can help decrease dependence on mining of raw materials for producing cathodes, while preventing commodity prices from rising. This study employed chemically delithiated cathodes that are analogous to spent cathodes but free of impurities to fundamentally elucidate the effectiveness of cathode regeneration. Two lithium cobalt oxides (LCOs) at different degrees of delithiation were synthesized via chemical delithiation. Their material and electrochemical characteristics were systematically compared before and after hydrothermal-based cathode regeneration. The material and electrochemical characteristics were further evaluated and compared with those of pristine LCO. Both LCOs, at high and low states of health (SOH), recovered their reversible capacity and cycle performance comparable to those of pristine LCO. However, the high-rate performance (2C) of the regenerated LCOs was not comparable to that of pristine LCO. The slight increase in cell resistance of the regenerated LCOs was attributed to their lower high-rate performance, which was identified as a key challenge of cathode regeneration. Our study provides valuable insights into the effectiveness of cathode regeneration by elucidating the process underlying regeneration of disordered Li-deficient LCOs at different levels of SOH.more » « less
-
Na-ion batteries have taken more interest in recent years as an alternative battery chemistry to Li-ion batteries because of material abundance, cost, and sufficient volumetric energy density for large-scale energy storage applications. However, Na-ion batteries suffer from rapid capacity fade associated with chemo-mechanical instabilities such as the formation of resistive solid-electrolyte / cathode-electrolyte interphase (SEI/CEI) layers, irreversible phase formations, and particle fracture. The cathode materials are fragile, especially metal oxides, therefore Na-ion cathodes are more prone to mechanical deformations upon larger volumetric expansions/reductions during Na-ion intercalation. Electrolyte additives have been utilized to improve the electrochemical performance of Li-ion and Na-ion batteries by modifying the chemistry of the SEI layers. In situ stress measurements on Si anode in Li-ion batteries demonstrated the generation of less mechanical deformations in the electrode when cycled in the presence of FEC additives.1However, there is not much known about the impact of electrolyte additives on the chemo-mechanical properties of CEI layers in Na-ion battery cathodes. Furthermore, the question still stands about how the electrolyte additives may impact the mechanical stability of the Na-ion cathodes. To address this gap, we systematically investigated the role of FEC additives on the electrochemical performance and associated chemo-mechanical instabilities in NaCrO2 cathodes. Experiments were performed in organic electrolytes with/without FEC additives. First, the talk will start with presenting the impact of FEC additives on the capacity retention and cyclic voltammeter profiles of NaCrO2 cathodes. Then, digital image correlation and multi-beam optical stress sensor techniques were employed to probe electrochemical strain and stress generation in the composite NaCrO2 cathodes during electrochemical cycling in organic electrolytes with/without FEC additives. Surface chemistry of the NaCrO2 cathodes after cycling was investigated with the FT-IR measurements. In summary, the talk will present contrast differences in the electrochemical and chemo-mechanical properties of NaCrO2 cathodes when cycled in the presence of the FEC additives. Acknowledgement: This work is supported by National Science Foundation (award number 2321405). Reference: 1) Tripathi et al 2023 J. Electrochem. Soc. 170 090544more » « less
-
Wang, Dong (Ed.)Lithium-ion batteries have been extensively used to power portable electronics, electric vehicles, and unmanned aerial vehicles over the past decade. Aging decreases the capacity of Lithium-ion batteries. Therefore, accurate remaining useful life (RUL) prediction is critical to the reliability, safety, and efficiency of the Lithium-ion battery-powered systems. However, battery aging is a complex electrochemical process affected by internal aging mechanisms and operating conditions (e.g., cycle time, environmental temperature, and loading condition). In this paper, a physics-informed machine learning method is proposed to model the degradation trend and predict the RUL of Lithium-ion batteries while accounting for battery health and operating conditions. The proposed physics-informed long short-term memory (PI-LSTM) model combines a physics-based calendar and cycle aging (CCA) model with an LSTM layer. The CCA model measures the aging effect of Lithium-ion batteries by combining five operating stress factor models. The PI-LSTM uses an LSTM layer to learn the relationship between the degradation trend determined by the CCA model and the online monitoring data of different cycles (i.e., voltage, current, and cell temperature). After the degradation pattern of a battery is estimated by the PI-LSTM model, another LSTM model is then used to predict the future degradation and remaining useful life (RUL) of the battery by learning the degradation trend estimated by the PI-LSTM model. Monitoring data of eleven Lithium-ion batteries under different operating conditions was used to demonstrate the proposed method. Experimental results have shown that the proposed method can accurately model the degradation behavior as well as predict the RUL of Lithium-ion batteries under different operating conditions.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.adg4687
