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Han, Fudong

Publications and source records attributed to Han, Fudong.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Hydride-Based Interlayer for Solid-State Anode-Free Battery

Solid-state batteries (SSBs) are considered a promising approach to realizing an anode-free concept with high energy densities. However, the initial Coulombic efficiency (ICE) has remained insufficient for anode-free batteries using sulfide-based solid electrolytes (SEs). Herein, we incorporated a hydride-based interlayer, 3LiBH 4 -LiI (LBHI), between a typical sulfide SE, Li 6 PS 5 Cl, and the Cu current collector. Further, by investigating the Li plating and stripping behaviors and the (electro)chemical stability between SEs and plated Li, we demonstrated that LBHI can effectively improve interfacial stability, leading to an ICE exceeding 94% in anode-free half cells. This interlayer also improves Coulombic efficiencies and specific capacities in anode-free full cells. Furthermore, the utilization of LBHI enables one to study Li plating behaviors without interference from interfacial (electro)chemical instabilities. The analysis of stack pressure evolution during electrochemical cycling reveals that soft shorting in SSBs arises from both dendrite formation and deformation, offering insights into further optimizing solid-state anode-free batteries.

25 ENERGY STORAGE↗
DOE OSTI2023

Structural evolution during solution-based synthesis of Li 7 P 3 S 11 solid electrolyte by synchrotron X-ray total scattering

Solution-based synthesis has emerged as a promising approach for scalable and efficient synthesis of solid electrolytes (SEs). However, the ionic conductivity of solution-synthesized SEs is much lower than that of SEs synthesized by solid state approaches. The structural evolution during the synthesis of SEs is crucial to explaining the decreased ionic conductivities but has not been well understood. Here, in this work, we use synchrotron X-ray total scattering combined with pair distribution function (PDF) analysis to understand the structural evolution during annealing of the solution-processed precursor for the synthesis of Li 7 P 3 S 11 SEs. Combining Bragg diffraction and diffuse scattering, X-ray total scattering enables detection of structural information including phase transition and crystallinity. The results show that the formation of Li 7 P 3 S 11 glass-ceramic starts at 230 °C. Increasing the annealing temperature helps to improve the crystallinity, but the degree of crystallization is still lower than 70.3% even after annealing at 290 °C when thermal decomposition of Li 7 P 3 S 11 to Li 4 P 2 S 6 has occurred. PDF analysis also revealed the existence of acetonitrile used in the solution-based synthesis in the SEs after annealing at high temperatures. The results rationalize the synthesis–property relationship, explain why annealing at 290 °C provides the highest ionic conductivity at the studied temperatures due to an optimal balance for achieving a high crystallinity while suppressing severe decomposition of Li 7 P 3 S 11 , and provide novel insights to develop approaches for synthesizing superior Li 7 P 3 S 11 SEs on a large scale.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Grain growth kinetics of the gamma phase metallic uranium

We report metallic uranium is a leading fuel form for sodium cooled fast reactors as an enabling technology of future nuclear energy systems. Mechanistic understanding of fuel behaviors and kinetics under thermodynamic equilibrium and highly non-equilibrium conditions are essential for evaluating fuel performance. It is important to understand and predict the grain and pore evolutions of metallic fuels under thermal and irradiation conditions. However, very limited data are available on the grain growth kinetics and mechanisms of pure gamma phase uranium. In this paper, the pure gamma uranium pellets with different grain structures were fabricated by combining high-energy ball milling and spark plasma sintering. Isothermal annealing tests were performed to investigate the grain growth behavior of the pure gamma phase uranium with different initial grain sizes. A parabolic relationship in grain growth with time was identified for the submicron-sized (374 nm) sample. In contrast, for the nano-sized (137 nm) sample, the grain growth shows a linear relationship with time. The activation energies of grain growth were determined as 199.5 KJ/mol and 80.6 KJ/mol for nano-sized and submicron-sized grain structures, respectively. For the nano-sized sample, the rate-control step of grain growth is dominated by the triple-junction migration, in which the grain boundary triple junction drags the grain growth, leading to a higher activation energy than the bulk diffusion. The dominating mechanism for the submicron-sized sample is grain boundary diffusion. The mechanistic understanding and critical data obtained on the kinetics of pure uranium phases will be useful to evaluate fuel behavior under thermodynamic equilibrium conditions and develop a high fidelity model to predict fuel performance.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Enabling Conversion-Type Iron Fluoride Cathode by Halide-Based Solid Electrolyte

The practical application of low-cost and energy-dense iron fluoride cathodes has been hindered by the first cycle electrochemical irreversibility, cycling instability, and large voltage hysteresis. Here, we report that these challenges may be overcome by the utilization of halide-based solid electrolytes (SEs). The excellent electrochemical stability of halide-based SEs enables a complete conversion and deconversion of FeF 2 which cannot be achieved with sulfide-based SEs. Due to restricted and reversible decomposition of SE, prevention of Fe dissolution, mechanical confinement of active material, as well as improved electrode kinetics, solid-state FeF 2 cathode with halide-based SE demonstrated superior electrochemical performance compared with FeF 2 electrodes in liquid electrolytes, with a high 1st cycle coulombic efficiency (~100 %), high specific capacity (~600 mAh/g), long cycle life (>100 cycles) and high-rate performance (up to 2C). In conclusion, our results suggest solidifying the batteries may be a viable approach to addressing the long-standing key challenges of iron fluoride cathodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Rational Designed Mixed-Conductive Sulfur Cathodes for All-Solid-State Lithium Batteries

All-solid-state lithium–sulfur batteries (ASSLSBs) hold great promise for safe and high-energy-density energy storage. However, developing high-performance sulfur cathodes has been proven difficult due to low electronic and ionic conductivities and large volume change of sulfur during charge and discharge. Here, we reported an approach to synthesize sulfur cathodes with a mixed electronic and ionic conductivity by infiltrating a solution consisting of Li 3 PS 4 (LPS) solid electrolyte and S active material into a mesoporous carbon (CMK-3). This approach leads to a uniform dispersion of amorphous Li 3 PS 7 (L 3 PS) catholyte in an electronically conductive carbon matrix, enabling high and balanced electronic/ionic conductivities in the cathode composite. The inherent porous structure of CMK-3 also helps to accommodate the strain/stress generated during the expansion and shrinkage of the active material. In sulfide-based all-solid-state batteries with Li metal as the anode, this cathode composite delivered a high capacity of 1025 mAh g –1 after 50 cycles at 60 °C at 1/8C. This work highlights the important role of high and balanced electronic and ionic conductivities in developing high-performance sulfur cathodes for ASSLSBs.

25 ENERGY STORAGE↗
DOE OSTI2019

All-temperature batteries enabled by fluorinated electrolytes with non-polar solvents

We report carbonate electrolytes are commonly used in commercial non-aqueous Li-ion batteries. However, the high affinity between the solvents and the ions and high flammability of the carbonate electrolytes limits the battery operation temperature window from -20 to +50 °C and voltage window from 0.0 to 4.3 V. Here we tamed the affinity between solvents and Li ions of the nonflammable electrolytes by dissolving the fluorinated electrolytes into highly fluorinated non-polar solvents. The tamed non-flammable electrolytes have a wide voltage window of 0.0 to 5.6 V, wide liquid range from -125 to +70 °C, high Li-ion transference number of 0.7, and low Li-ion desolvation energy. In a wide temperature from -95 to +70 °C, the electrolytes enable both commercial graphite anodes and LiNi0.8Mn0.1Co0.1O2 cathodes to achieve a high Coulombic efficiencies of >99.9%, and the most aggressive Li2 anodes and 5.4 V LiCoMnO4 to achieve a Coulombic efficiencies of >99.4% and 99%, respectively. Even at -85 °C, the LiNi 0.8 Co 0.15 Al 0.05 O 2 ||Li battery can still deliver ~50% of room-temperature capacity

25 ENERGY STORAGE↗
DOE OSTI2019

High electronic conductivity as the origin of lithium dendrite formation within solid electrolytes

Solid electrolytes (SEs) are widely considered as an ‘enabler’ of lithium anodes for high-energy batteries. However, recent reports demonstrate that the Li dendrite formation in Li 7 La 3 Zr 2 O 12 (LLZO) and Li 2 S–P 2 S 5 is actually much easier than that in liquid electrolytes of lithium batteries, by mechanisms that remain elusive. Here we illustrate the origin of the dendrite formation by monitoring the dynamic evolution of Li concentration profiles in three popular but representative SEs (LiPON, LLZO and amorphous Li 3 PS 4 ) during lithium plating using time-resolved operando neutron depth profiling. Although no apparent changes in the lithium concentration in LiPON can be observed, we visualize the direct deposition of Li inside the bulk LLZO and Li 3 PS 4 . Furthermore, our findings suggest the high electronic conductivity of LLZO and Li 3 PS 4 is mostly responsible for dendrite formation in these SEs. Lowering the electronic conductivity, rather than further increasing the ionic conductivity of SEs, is therefore critical for the success of all-solid-state Li batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Fluorinated solid electrolyte interphase enables highly reversible solid-state Li metal battery

Solid-state electrolytes (SSEs) are receiving great interest because their high mechanical strength and transference number could potentially suppress Li dendrites and their high electrochemical stability allows the use of high-voltage cathodes, which enhances the energy density and safety of batteries. However, the much lower critical current density and easier Li dendrite propagation in SSEs than in nonaqueous liquid electrolytes hindered their possible applications. Herein, we successfully suppressed Li dendrite growth in SSEs by in situ forming an LiF-rich solid electrolyte interphase (SEI) between the SSEs and the Li metal. The LiF-rich SEI successfully suppresses the penetration of Li dendrites into SSEs, while the low electronic conductivity and the intrinsic electrochemical stability of LiF block side reactions between the SSEs and Li. The LiF-rich SEI enhances the room temperature critical current density of Li 3 PS 4 to a record-high value of >2 mA cm -2 . Moreover, the Li plating/stripping Coulombic efficiency was escalated from 88% of pristine Li 3 PS 4 to more than 98% for LiF-coated Li 3 PS 4 . In situ formation of electronic insulating LiF-rich SEI provides an effective way to prevent Li dendrites in the SSEs, constituting a substantial leap toward the practical applications of next-generation high-energy solid-state Li metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2018

Architectural design and fabrication approaches for solid-state batteries

Solid-state batteries are promising candidates for energy storage due to their potential advantages in safety, working temperature range, and energy density compared to traditional liquid-electrolyte-based batteries. Rational battery architecture design and a scalable fabrication approach are critical to realize solid-state batteries. In this article, we present the architecture, fabrication procedure, and related challenges of sulfide and oxide electrolyte-based solid-state batteries. Approaches toward intimate solid–solid contact, thin solid-electrolyte fabrication, and scale-up production are discussed. Lastly, we discuss the future research directions of solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2018

High Energy-Density and Reversibility of Iron Fluoride Cathode Enabled Via an Intercalation-Extrusion Reaction

Iron fluoride, an intercalation-conversion cathode for lithium ion batteries, promises a high theoretical energy density of 1922 Wh Kg –1 . However, poor electrochemical reversibility due to repeated breaking/reformation of metal-fluoride bonds poses a grand challenge for its practical application. Here we report that both a high reversibility over 1000 cycles and a high capacity of 420 mAh g –1 can be realized by concerted doping of cobalt and oxygen into iron fluoride. In the doped nanorods, an energy density of ~1000 Wh Kg –1 with a decay rate of 0.03% per cycle is achieved. The anion and cation’s co-substitutions thermodynamically reduce conversion-reaction potential and shift the reaction from less reversible intercalation-conversion reaction in iron fluoride to a highly reversible intercalation-extrusion reaction in doped material. Furthermore, the co-substitution strategy to tune the thermodynamic features of the reactions could be extended to other high energy conversion materials for improved performance.

25 ENERGY STORAGE↗