An official website of the United States government
Aqueous Li-ion batteries (ALIBs) are an important class of battery chemistries owing to the intrinsic non-flammability of aqueous electrolytes. However, water is detrimental to most cathode materials and could result in rapid cell failure. Identifying the degradation mechanisms and evaluating the pros and cons of different cathode materials are crucial to guide the materials selection and maximize their electrochemical performance in ALIBs. In this study, we investigate the stability of LiFePO4(LFP), LiMn2O4(LMO) and LiNi0.8Mn0.1Co0.1O2(NMC) cathodes, without protective coating, in three different aqueous electrolytes, i.e., salt-in-water, water-in-salt, and molecular crowding electrolytes. The latter two are the widely reported “water-deficient electrolytes.” LFP cycled in the molecular crowding electrolyte exhibits the best cycle life in both symmetric and full cells owing to the stable crystal structure. Mn dissolution and surface reduction accelerate the capacity decay of LMO in water-rich electrolyte. On the other hand, the bulk structural collapse leads to the degradation of NMC cathodes. LMO demonstrates better full-cell performance than NMC in water-deficient aqueous electrolytes. LFP is shown to be more promising than LMO and NMC for long-cycle-life ALIB full cells, especially in the molecular crowding electrolyte. However, none of the aqueous electrolytes studied here provide enough battery performance that can compete with conventional non-aqueous electrolytes. This work reveals the degradation mechanisms of olivine, spinel, and layered cathodes in different aqueous electrolytes and yields insights into improving electrode materials and electrolytes for ALIBs.
more »
« less
Single‐Step Electrochemical Battery Recycling
Abstract Sustainable battery production is a major challenge for the future of electrification with the rise in battery production leading to a massive increase in demand for battery cathode materials. Needed are environmentally responsible ways to recycle used cathodes into new cathodes to create a circular economy for batteries. While some battery recycling and recovery techniques for battery components are developed, they can involve costly and environmentally impactful multi‐step processes. This work demonstrates for the first time the simultaneous dissolution and electrochemical deposition of Li‐ion transition metal oxide cathodes, providing a path to directly fabricate new battery cathodes from old battery cathodes. The LiCoO2cathodes formed via this recycling process exhibit near‐theoretical capacities, are binder and additive‐free, and are phase pure. Technoeconomic and life cycle analyses show the simultaneous dissolution and electrochemical deposition process is less costly and environmentally harmful than traditional pyrometallurgical, hydrometallurgical, and direct recycling methods. This method has major potential impacts and advantages on the industrial scale as it creates battery materials in fewer steps at a lower cost and with a lower environmental impact than current battery recycling methods.
more »
« less
- Award ID(s):
- 2037898
- PAR ID:
- 10629015
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 36
- Issue:
- 2
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
The rapid expansion of electric vehicle (EV) fleet calls for large number of lithium-ion batteries to be recycled at their end-of-life. Various recycling methods have been developed or under development to recover the high-value materials from retired lithium-ion batteries. Amongst these methods, direct recycling techniques have been developed and reported to recycle battery materials for reuse in new battery manufacturing since the electrochemical properties of the recycled materials can be fully recovered to the same level of pristine materials. In literature, innovative sintering processes have been developed to recover the composition and crystal structure of spent cathode materials; hydrothermal regeneration processes have been reported to regenerate the spent cathode materials in the solvents at a moderate temperature, followed by the high-temperature short annealing process. The regenerated cathode materials show the same specific capacity and cycling performance as those of pristine materials. The electrochemical regeneration method is applied to fully recover the electrochemical performance of cathode material with stable crystal structure. While the direct recycling techniques are still under development, their future applications in industry are still not clear. This study aims to classify and summarize state-of-the-art of the direct recycling methods, and evaluate the regenerated cathode materials’ performance and the application potential to be used for manufacturing of new lithium-ion batteries in future. The results will help increase understanding of the direct recycling technologies and facilitate the associated R&D for future industrial scaling-up of direct recycling processes for retired lithium ion batteries from electric vehicles.more » « less
-
Cathodes of lithium-ion batteries (LIBs) significantly impact the environmental footprint, cost, and energy performance of the battery-pack. Hence, sustainable production of Li-ion battery cathodes is critically required for ensuring cost-effectiveness, environmental benignity, consumer friendliness, and social justice. Battery chemistry largely determines individual cell performance as well as the battery pack cost and life cycle greenhouse gas emission. Continuous manufacturing platforms improve production efficiency in terms of product yield, quality and cost. Spent-battery recycling ensures the circular economy of critical elements that are required for cathode production. Innovations in fast-charging LIBs are particularly promising for sustainable e-mobility with a reduced carbon footprint. This article provides an overview of these research directions, emphasizing strategies for low-cobalt cathode development, recycling processes, continuous production and improvement in fast-charging capability.more » « less
-
The growing demands for high-energy density electrical energy storage devices stimulate the coupling of conversion-type cathodes and lithium (Li) metal anodes. While promising, the use of these “Li-free” cathodes brings new challenges to the Li anode interface, as Li needs to be dissolved first during cell operation. In this study, we have achieved a direct visualization and comprehensive analysis of the dynamic evolution of the Li interface. The critical metrics of the interfacial resistance, Li growth, and solid electrolyte interface (SEI) distribution during the initial dissolution/deposition processes were systematically investigated by employing multidimensional analysis methods. They include three-electrode impedance tests, in situ atomic force microscopy, scanning electrochemical microscopy, and cryogenic scanning transmission electron microscopy. The high-resolution imaging and real-time observations show that a loose, diffuse, and unevenly distributed SEI is formed during the initial dissolution process. This leads to the dramatically fast growth of Li during the subsequent deposition, deviating from Fick’s law, which exacerbates the interfacial impedance. The compactness of the interfacial structure and enrichment of electrolyte species at the surface during the initial deposition play critical roles in the long-term stability of Li anodes, as revealed by operando confocal Raman spectroscopic mapping. Our observations relate to ion transfer, morphological and structural evolution, and Li (de)solvation at Li interfaces, revealing the underlying pathways influenced by the initial dissolution process, which promotes a reconsideration of anode investigations and effective protection strategies.more » « less
-
Abstract Lithium‐ion battery electrodes are manufactured using a new additive manufacturing process based on dry powders. By using dry powder‐based processing, the solvent and its associated drying processes in conventional battery process can be removed, allowing for large‐scale Li‐ion battery production to be more economically viable in markets such as automotive energy storage systems. Uniform mixing distribution of the additive materials throughout the active material is the driving factor for manufacturing dry powder‐based Li‐ion batteries. Therefore, this article focuses on developing a physical model based on interfacial energies to understand the mixing characteristics of the dry mixed particulate materials. The mixing studies show that functional electrodes can be manufactured using dry processing with binder and conductive additive materials as low as 1 wt% due to the uniformly distributed particles. Electrochemical performance of the dry manufactured electrodes with reduced conductive and binder additive is promising as the cells retained 77% capacity after 100 cycles. While not representative of the best possible electrochemical performance of Li‐ion batteries, the achieved electrochemical performance of the reduced conductive and binder additive electrodes with LiCoO2as the active material confirms the well distributed nature of the additive particles throughout the electrode matrix.more » « less
