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Develop advanced nuclear fuel cycle separation and waste management technologies that improve current fuel cycle performance and enable a sustainable fuel cycle, with minimal processing, waste generation, and potential for material diversion.
Multiple recycle of long-lived actinides has the potential to greatly reduce the required storage time for spent nuclear fuel or high level nuclear waste. This is generally thought to require fast reactors as most transuranic (TRU) isotopes have low fission probabilities in thermal reactors. Reduced-moderation LWRs are a potential alternative to fast reactors with reduced time to deployment as they are based on commercially mature LWR technology. Thorium (Th) fuel is neutronically advantageous for TRU multiple recycle in LWRs due to a large improvement in the void coefficient. If Th fuel is used in reduced-moderation LWRs, it appears neutronically feasible to achieve full actinide recycle while burning an external supply of TRU, with related potential improvements in waste management and fuel utilization. In this paper, the fuel cycle of TRU-bearing Th fuel is analysed for reduced-moderation PWRs and BWRs (RMPWRs and RBWRs). RMPWRs have the advantage of relatively rapid implementation and intrinsically low conversion ratios. However, it is challenging to simultaneously satisfy operational and fuel cycle constraints. An RBWR may potentially take longer to implement than an RMPWR due to more extensive changes from current BWR technology. However, the harder neutron spectrum can lead to favourable fuel cycle performance. A two-stage fuel cycle, where the first pass is Th-Pu MOX, is a technically reasonable implementation of either concept. The first stage of the fuel cycle can therefore be implemented at relatively low cost as a Pu disposal option, with a further policy option of full recycle in the medium term. (authors)
Evaluation of cycle performance when sCO2 closed loop Brayton cycles are coupled with fossil fuel combustion and carbon capture technologies
The layer-structured Li[Ni x Co y Mn 1-x-y ]O 2 (NCM) cathode materials have been the best choice for increasing electric vehicle driving distance per charge. The high Ni layered oxide represents successfully commercialized NCM cathodes (such as NCM622 and NCA) in lithium-ion batteries (LIBs) for EV applications due to their high energy density and acceptable cycling stability. However, the price of cobalt, the key element within LIBs for stability, has nearly tripled over the past few years due to increased demand from the cell phone industry. As mentioned in the DOE Funding Opportunity Announcement, the current materials shortage will also cause speculation for a future global shortage. Therefore, to meet the requirement and sustainability of the next-generation long-range and low-cost EVs, developing cathode materials with low-Co content to achieve higher energy density and lower cost is both essential and urgent. The overarching objective of this work is to develop stabilized NCM cathode materials with low Co content (namely LiNi x Co y Mn 1-x-y O 2 , y ≤ 0.04) to meet DOE’s goal of reducing Co loading below 50 mg Wh -1 while maintaining energy density greater than 600 Wh kg -1 based on cathode material. Via various dopings and coatings scalable methods, we explored and enhanced the cycling performance of low-cobalt cathodes. The final obtained NCM cathodes paired with graphite anode aim to deliver batteries with a high initial specific energy density of over 240 Wh kg -1 and a low capacity fading rate of less than 20% in 1000 cycles under a C/3 discharge rate. To accomplish this goal, a multidisciplinary team with several co-investigators has been formed from three organizations: The Pennsylvania State University (PSU), Oak Ridge National Laboratory (ORNL), and Pacific Northwest National Laboratory (PNNL). The PI and co-investigators are Dr. Donghai Wang (PI) from PSU with expertise in the synthesis of nanostructured materials and manipulation of interfacial properties of electrochemically active materials, Dr. Jagjit Nanda, with substantial knowledge of and expertise in state-of-the-art cathodes from ORNL, Dr. Chao-Yang Wang with significant experience in advanced cell design and fabrication and cell diagnostics from PSU, and Dr. Chongmin Wang with world-wide known expertise of advance atomic scale characterization of electrode materials from PNNL. Furthermore, this project will leverage and synergistically work with the current DOE-funded programs on battery materials at PSU and ORNL and electrode materials characterization at PNNL. During this funded period, we have accomplished milestones stated as follows: • Scale up production of LiFePO 4 (LFP) coated NCM811 with a production of 300g/batch. Fifteen (≥2 Ah) pouch cells with LFP-coated NCM811 cathode are delivered. Self-evaluated pouch cells in PSU show superior over 80% capacity retention performance even after 1500 cycles at C/3 rate. • Various cations (Al, Ti, Zr, and Mo) substitute cobalt in low-cobalt partially and Co-free cathodes. Their effects on crystal structure and electrochemical behavior are explored. • Phosphate compounds as coating materials represent promising surface protection precursors for low-cobalt cathode materials. Therefore, several metal phosphates were selected for improving the NMC cycling performance and are regarded as effective approaches for a scalable and practical surface protection method. • Production of NCM92, where Nickel content is 92% among transition metals, is scaled up from synthesis to coating and heat treatment procedures. Fifteen 2.7Ah pouch cells with Ti-doped NCM92 cathodes and industrial graphite anode are delivered to Idaho National Lab for testing.
Design and performance data for 81 Ah FNC cells are given. The conclusions are: that a sealed Ni-Cd cells are not limited to 50 Ah with the FNC design; energy densities of 40 Wh/kg in a conservative high Cd, high electrolyte design have been demonstrated; uniform ATP data and LEO cycling performance is being demonstrated; internal cell pressures remain low under all conditions; and no conditioning is necessary under any LEO profile; accelerated LEO cycling exhibits performance well beyond traditional space Ni-Cd cells.
In this paper, to reveal the effects of Co-doping on the electrochemical performance of micro-sized LiNi 0.5 Mn 1.5 O 4 (LNMO), undoped LNMO and Co-doped LiCo 0.1 Ni 0.45 Mn 1.45 O 4 (LCoNMO) are synthesized via a PVP-combustion method and calcined at 1000 °C for 6 h. SEM and XRD analyses suggest that Co-doping decreases the particle size and the Li z Ni 1-z O 2 impurity at the calcination temperature of 1000 °C. LCoNMO has much better rate capability while its specific capacity at C/5 is 10% lower than that of LNMO. At 15 C rate, their specific capacities are closed, and the LCoNMO delivers 86.2% capacity relative to C/5, and this value for LNMO is only 77.0%. The D Li + values determined by potential intermittent titration technique (PITT) test of LCoNMO are 1–2 times higher than that of LNMO in most SOC region. The LCoNMO shows very excellent cycling performance, which is the best value compared with literatures. After 1000 cycles, the LCoNMO still delivers 94.1% capacity. Finally, moreover, its coulombic efficiency and energy efficiency keep at 99.84% and over 97.3% during 1 C cycling, respectively.
To spread lithium ion batteries into large-scale energy storage technologies, high ener-gy/power densities and long cycling life of carbon-based anodes must be achieved. This re-quires revolutionary design of the anode’s architectures that can facilitate the fast electronic and ionic transport, as well as accommodate the electrode structural instability. Here we re-port a thin-film electrode design and demonstrate its use in flexible, and large-area carbon-based anode assemblies. The fabrication of electrodes is realized by sputtering a graphite tar-get in the high-purity nitrogen atmosphere, then highly-defect nitrogen-doped carbon nano-fibers are deposited vertically onto copper substrates with a thin film configuration. The high-ly-defect nitrogen-doping enhances the lithium storage and transport, the orientation grown mechanism improves the charge transfer, and the compact configuration makes the high tap density possible. As a result, the thin films exhibit high specific capacities of ~ 500 mAh g-1, namely a volume capacity of ~ 100 mAh cm-3. They also exhibit stable cycle performance (400 mAh g-1 after 200 cycles) and good rate capability (450 mAh g-1 at 1 A g-1 rate). This work opens up a new carbon-based anode design by using sputtering technology for effec-tively incorporating high content nitrogen into carbon matrices. Such electrode architecture significantly improves the electrochemical performance of carbon-based materials.
Complex phase transitions induced by interlayer slides in layered cathode materials lead to poor cycling stability and rate capability for sodium-ion batteries. Herein, we design and prepare a new six-component high-entropy oxide (HEO) layered cathode O3–Na(Fe 0.2 Co 0.2 Ni 0.2 Ti 0.2 Sn 0.1 Li 0.1 )O 2 to enable highly reversible electrochemical reaction and phase-transition behavior. The HEO cathode exhibits good cycling performance (capacity retention of ~81% after 100 cycles at 0.5C) and outstanding rate capability (capacity of ~81 mA h g –1 at 2.0C) due to the higher sodium diffusion coefficient (above 5.75 × 10 –11 cm 2 s –1 ) than most reported O3-type cathodes. Moreover, the high-entropy cathode has superior compatibility with the hard carbon anode and delivers a specific capacity of 90.4 mA h g –1 (energy density of ~267.5 W h kg –1 ). Ex situ X-ray diffraction proves that the high-entropy designing effectively suppresses the intermediate phase change to achieve reversible O3–P3 phase evolution, and in turn stabilizes the layered structure. X-ray absorption spectroscopy and Mössbauer spectrum of 57 Fe suggest that Ni 2+ /Ni 3.5+ , Co 3+ /Co 3.5+ , and part of Fe 3+ /Fe 3.5+ redox reaction contribute the charge compensation. Finally, the enhanced performance can be attributed to the disordered distribution of multi-component transition metals in HEO suppressing the ordering of electric charges and sodium vacancies, thereby inhibiting the interlayer slide and phase transition.
Abstract The long‐term cycling performance, rate capability, and voltage stability of lithium (Li) metal batteries with LiNi 0.76 Mn 0.14 Co 0.10 O 2 (NMC76) cathodes is greatly enhanced by lithium bis(oxalato)borate (LiBOB) additive in the LiPF 6 ‐based electrolyte. With 2 % LiBOB in the electrolyte, a Li∥NMC76 cell is able to achieve a high capacity retention of 96.8 % after 200 cycles at C/3 rate (1 C=200 mA g −1 ), which is the best result reported for a Ni‐rich NMC cathode coupled with Li metal anode. The significantly enhanced electrochemical performance can be ascribed to the stabilization of both the NMC76 cathode/electrolyte and Li‐metal‐anode/electrolyte interfaces. The LiBOB‐containing electrolyte not only facilitates the formation of a more compact solid–electrolyte interphase on the Li metal surface, it also forms a enhanced cathode electrolyte interface layer, which efficiently prevents the corrosion of the cathode interface and mitigates the formation of the disordered rock‐salt phase after cycling. The fundamental findings of this work highlight the importance of recognizing the dual effects of electrolyte additives in simultaneously stabilizing both cathode and anode interfaces, so as to enhance the long‐term cycle life of high‐energy‐density battery systems.
A self-healing polymer (SHP) with abundant hydrogen bonds, appropriate viscoelasticity, and stretchability is a promising binder to improve cycle performance of Si microparticle anodes in lithium (Li) ion batteries. Besides high capacity and long cycle life, efficient rate performance is strongly desirable for practical Si anode implementation. Here in this paper, polyethylene glycol (PEG) groups are incorporated into the SHP, facilitating Li ionic conduction within the binder. The concept of the SHP-PEG binder involves improving the interface between Si microparticles and electrolytes after cycling based on the combination of self-healing ability and fast Li ionic conduction. Through the systematic study of mixing PEG M w and ratio, the polymeric binder combining SHP and PEG with Mw 750 in an optimal ratio of 60:40 (mol%) achieves a high discharging capacity of ≈2600 mA h g -1 , reasonable rate performance especially when >1C and maintains 80% of their initial capacity even after ≈150 cycles at 0.5C. The described concept for the polymeric binder, embedding both self-healing ability and high Li ionic conductivity, should be equally useful for next generation batteries utilizing high capacity materials which suffer from huge volume change during cycling.
Here in this paper, we explore the electrochemical mechanism of a novel rechargeable seawater battery system that uses seawater as the cathode material. Sodium is harvested from seawater while charging the battery, and the harvested sodium is discharged with oxygen dissolved in the seawater, functioning as oxidants to produce electricity. The seawater provides both anode (Na metal) and cathode (O 2 ) materials for the proposed battery. Based on the discharge voltage (~2.9 V) with participation of O 2 and the charge voltage (~4.1 V) with Cl 2 evolution during the first cycle, a voltage efficiency of about 73% is obtained. If the seawater battery is constructed using hard carbon as the anode and a Na super ion conductor as the solid electrolyte, a strong cycle performance of 84% is observed after 40 cycles.
Highlights: • MnO{sub 2}/HGC nanospheres are prepared by a cooperative template wrapping method. • MnO{sub 2}/HGC nanospheres possess large specific surface area. • MnO{sub 2}/HGC nanospheres are benefit for transmission of ions and electrons. • MnO{sub 2}/HGC electrodes exhibit a high specific capacitance. - Abstract: MnO{sub 2}-wrapped hollow graphitized carbon nanospheres (MnO{sub 2}/HGC) electrodes are prepared by a cooperative template wrapping method. hollow Graphitized carbon nanospheres (HGC) are firstly obtained by carbonizing phenolic resin followed by etching the SiO{sub 2} template, then the MnO{sub 2} ultrathin nanoplates are coated on the surfaces of the HGC nanospheres through a redox reaction between KMnO{sub 4} and HGC nanospheres. The as-prepared MnO{sub 2}/HGC hollow nanospheres possess porous structure and large specific surface area (∼230 m{sup 2} g{sup −1}). The specific capacitances of MnO{sub 2}/HGC nanosphere electrodes with different mass ratios of MnO{sub 2} to HGC are about 340–380 F g{sup −1} at a scan rate of 5 mV s{sup −1} in Na{sub 2}SO{sub 4} solution, and shows relative good cycling performance of the initial capacitance after 1000 cycles. The good specific capacitance is ascribed to the novel hollow nanosphere structure, which possesses high surface-to-volume ratio, and makes it easy for the mass diffusion of electrolyte and transmission of ions and electrons and also maintains the mechanical integrality.
Dendrites and dead lithium formation over prolonged cycling have long been challenges that hinder the safe implementation of metallic Li anodes. In this study, we employ polymer-stabilized liquid metal nanoparticles (LM-P NPs) of eutectic gallium indium (EGaIn) to create uniform Li nucleation sites enabling homogeneous lithium electrodeposition. Block copolymers of poly(ethylene oxide) and poly(acrylic acid) (PEO-b-PAA) were grafted onto the EGaIn surface, forming stabilized, well-dispersed NPs. Using a scalable spray coating approach, LM-P NPs were fabricated on copper current collectors, providing lithiophilic PEO sites and interactive carboxyl groups to guide Li deposition. The Li-EGaIn alloying process greatly reduced the Li + diffusion barrier, enabling fast Li transport through the coating layer, resulting in decreased nucleation overpotential. Therefore, about five times lower Li nucleation overpotential was obtained on the LM-P modified Cu with an optimal composition of the polymers than the bare Cu substrates. DFT computations was used to reveal the binding properties between the LM-P layer and Li. Due to the regulated Li plating/stripping process, as-obtained 30 μm Li anodes paired with LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM8 11 ) with a negative/positive electrode capacity (N/P) ratio ~ 10 exhibited stable cycling performance at 0.5C for over 250 cycles, with an average Coulombic efficiency of 99.55%. Ultrathin Li (1 μm) anodes with an N/P ratio ~ 0.6 were also demonstrated in Li|LiFePO 4 cells, which examined the stabilization of Li by LM-P NPs and monitored practical loadings of Li anodes that are close to anode-free systems.
As state-of-the-art (SOA) lithium-ion (Li-ion) batteries approach their specific energy limit (~250 Wh kg -1 ), layer-structured, nickel-rich (Ni-rich) lithium transition metal oxide-based cathode materials, e. g., LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811), have attracted great interest owing to their practical high specific capacities (>200 mAhg -1 ). Coupled with their high average discharge voltages (~4 V vs Li/Li + ), Ni-rich cathode-based lithium batteries possess a great potential to achieve much higher specific energies (>350 Wh kg -1 at the cell level) than the SOA Li-ion counterparts. In addition, Ni-rich oxides are low-cost battery cathode materials due to their low cobalt contents. However, Ni-rich cathode-based lithium batteries suffer quick capacity degradations upon cycling, particularly at high upper cutoff voltages (e.g., ≥= 4.5 V vs Li/Li + ), due to crystal structure changes of the active cathode materials and parasitic side reactions at the electrolyte/electrode interfaces. In this study, a fluorinated-solvent-based, high-voltage stable electrolyte (HVE), i.e., 1 M Li bis(trifluoromethanesulfonyl)imide (LiTFSI) in fluoroethylene carbonate (FEC), bis(2,2,2-trifluoroethyl) carbonate (FDEC), and methyl (2,2,2-trifluoroethyl) carbonate (FEMC) with Li difluoro(oxalate)borate (LiDFOB) additive, was formulated and evaluated in Li/NMC811 battery cells. Further, to the best of our knowledge, this class of electrolyte has not been investigated for Ni-rich cathode-based lithium batteries. Li/NMC811 cells with HVE exhibited a superior long-term cycle performance stability, maintaining ~80% capacity after ~500 cycles at a high cutoff voltage of 4.5 V (vs Li/Li + ) than a baseline carbonate-solvent-based electrolyte (BE). The superior cycle stability of the Li/NMC811 cells is attributed to the inherently high-voltage stability of HVE, supported by the physical and electrochemical analyses. This conclusion is supported by our density functional theory (DFT) modeling where HVE shows a less tendency of deprotonation/oxidation than BE, leading to the observed cycle stability. The findings in this study are important to help tackle the technical challenges facing Ni-rich cathode-based lithium batteries to realize their high energy density potentials with a long cycle life.
Nickel (Ni)-rich layered oxides such as LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) represent one of the most promising candidates for next-generation high-energy lithium-ion batteries (LIBs). However, the pristine Ni-rich cathode materials usually suffer from poor structural stability during cycling. In this work, we demonstrate a simple but effective approach to improve the cycling stability of the NCM622 cathode by dry coating of ultrastable Li 3 V 2 (PO 4 ) 3 -carbon (LVP-C) nanoparticles, which leads to a robust composite cathode (NCM622/LVP-C) without sacrificing the specific energy density compared with pristine NCM622. The optimal NCM622/LVP-C composite presents a high specific capacity of 162 mA h g -1 at 0.5 C and excellent cycling performance with 85.0% capacity retention after 200 cycles at 2 C, higher than that of the pristine NCM622 (67.6%). Systematic characterization confirms that the LVP-C protective layer can effectively reduce the side reactions, restrict the cation mixing of NCM622 and improve its structural stability. Moreover, the NCM622/LVP-C||graphite full cells also show a commercial-level capacity of 3.2 mA h cm -2 and much improved cycling stability compared with NCM622/LVP-C||graphite full cells, indicating the great promise for low-cost, high-capacity and long-life LIBs.
Lithium (Li)-magnesium (Mg) alloy with limited Mg amount, which can also be called Mg-doped Li (Li-Mg), has been considered as a potential alternative anode for high energy density rechargeable Li metal batteries. However, the optimum doping-content of Mg in Li-Mg anode and the mechanism of the improved performance are not well understood. In this study, density functional theory (DFT) calculations are used to investigate the effect of Mg amount in Li-Mg anode. The Li-Mg with about 5 wt. % Mg (abbreviated as Li-Mg5) has the lowest absorption energy of Li, thus all the surface area can be “controlled” by Mg atoms, leading to the smooth and continuous deposition of Li on the surface around the Mg center. A localized high concentration electrolyte enables Li-Mg5 to exhibit the best cycling stability in Li metal batteries with high-loading cathode and lean electrolyte under 4.4 V high-voltage, which is approaching the demand of practical application. This electrolyte also helps generate an inorganic-rich solid electrolyte interphase, which leads to smooth, compact and less corrosion layer on the Li-Mg5 surface. Both theoretical simulations and experimental results prove that Li-Mg5 has optimum Mg content and gives best battery cycling performance.