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At least 469 records · Page 26

Dual-shell silicate and alumina coating for long lasting and high capacity lithium ion batteries

In this work we demonstrate a theory-driven, novel dual-shell coating system of Li 2 SrSiO 4 and Al 2 O 3 , achieved via a facile and scalable sol-gel technique on LiCoO 2 electrode particles. The optimal thickness of each coating can lead to increased specific capacity (~185 mAh/g at 0.5 C-rate) at a cut-off potential of 4.5 V, and greater cycling stability at very high C rates (up to 10 C) in half-cells with lithium metal. The mechanism of this superior performance was investigated using a combination of X-ray and electron characterization methods. It shows that the results of this investigation can inform future studies to identify still better dual-shell coating schemes, achieved by such industrially feasible techniques, for application on similar, nickel-rich cathode materials.

25 ENERGY STORAGE↗

Atomic-scale tuned interface of nickel-rich cathode for enhanced electrochemical performance in lithium-ion batteries

The Ni-rich layered LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC6 22 ) is one promising cathode for lithium-ion batteries (LIBs), but suffers from poor cycling stability under high cutoff potentials. The performance degradation was reflected as capacity fading and voltage drop, having their roots in instable interface of NMC622. Aimed at improving interfacial stability, in this study, we deposited nanoscale ZrO 2 coatings conformally over NMC622 cathodes using atomic layer deposition (ALD). We found that, under a high cutoff voltage (4.5 V), the ALD ZrO 2 coatings evidently improved the performance of NMC622 cathode, showing better cyclability and higher sustainable capacity. In addition, the ALD coatings dramatically boosted the rate capability of NMC622. All these compelling performance results are ascribed to the atomic-scale tunable ZrO 2 coatings via ALD, which create stable interface and thereby inhibit unfavorable evolutions. In the study, we utilize a suite of characterization tools and various analyses to clarify the effects of ALD ZrO 2 coatings. This study will be helpful for improving the performance of nickel-rich cathodes via interfacial engineering using ALD.

25 ENERGY STORAGE↗

Potential of porous nodal-line semi-metallic carbon for sodium-ion battery anode

As an alternative to lithium-ion batteries (LIBs), sodium-ion batteries (SIBs) have attracted much attention because sodium is abundant, cost-effective, and environmentally benign. However, due to the larger size of Na-ion compared to the Li-ion, graphite does not work well as an anode for SIBs, as it does for LIBs. In this work, based on first-principles calculations, we show that the recently proposed topological semi-metallic carbon, HZGM-42, has great potential as an anode material for SIBs. With a large capacity of 318.5 mAhg -1 , low diffusion barrier of 0.08–0.21 eV, low average open-circuit voltage of 0.43 V, and a small volume expansion of 1.85%, the all-carbon topological quantum HZGM-42 has high energy density, good rate capability, and excellent cycling stability and can serve as a universal anode material for both LIBs and SIBs.

25 ENERGY STORAGE↗

Etching-assisted upcycling of Ni-lean to Ni-rich cathode materials

Upcycling is recognized as a sustainable recycling approach for spent lithium-ion batteries. However, existing upcycling methods typically involve intricate pretreatment or post-treatment steps, complicating their practical application. Here, in this study, we propose a straightforward, etching-assisted upcycling method that effectively transforms polycrystalline Ni-lean cathodes into high-performance single crystal Ni-rich cathodes. During the etching step, nickel acetate was dissolved into acetic acid and then polycrystalline NMC111 are etched in the solution. Finally, polycrystalline NMC111 are converted into single crystal particles coated with amorphous nickel acetate. This significantly enhances elemental diffusion during subsequent sintering by minimizing both particle size and the contact distance between NMC111 and nickel acetate. As elemental diffusion is improved and acetate ions decompose completely during sintering, the process requires neither additional pretreatment nor post-treatment. The resulting cathode materials (Etched-UP622) exhibit superior structural and electrochemical properties compared to the Control622, achieving an energy density of 719.7 Wh/kg, approximately 56.7 mAh/g higher than Control622 and 125.5 Wh/kg higher than NMC111. Etched-UP622 also delivers higher discharge capacity, improved rate performance and cycling stability, surpassing Control622 and NMC111. Meanwhile, NMC811 also can be synthesized by the proposed strategy, and the discharge capacity can reach 166.9 mAh/g at 1C, similar to 14 mAh/g higher than Control811. Overall, this etching-assisted strategy simplifies the upcycling process and offers a scalable, sustainable route for producing high-quality cathode materials.

Acid etching↗

Solvation-guided inhibition of manganese dissolution of lithium- and manganese- rich cathode via cyclic carbonate molecular engineering

Lithium and manganese-rich (LMR) layered oxides represent a leading class of high-energy cathode materials, but their practical realization is fundamentally limited by severe manganese (Mn) dissolution, a process that triggers structural degradation and rapid capacity fade. While mitigation efforts have predominantly focused on interfacial engineering, the intrinsic contribution of bulk electrolyte solvation to this degradation pathway remains largely unexplored, primarily due to the difficulty of deconvolving its effects from concurrent cathode-electrolyte interphase (CEI) formation. Here, we report an experimental design to isolate the role of solvation. We systematically varied the electrolyte solvent solvation power by substituting the strongly coordinating ethylene carbonate (EC) with its weaker coordinating fluorinated derivatives, fluoroethylene carbonate (FEC) and trans-4,5-Difluoro-1,3-dioxolan-2-one (DFEC), while maintaining a consistent interfacial chemistry. Remarkably, the electrolyte formulated with the weakest solvent, DFEC, exhibits superior cycling stability, suppressing Mn dissolution by up to 63% relative to the conventional EC-based system. Post-mortem analysis unequivocally attributes this performance enhancement to the preservation of the LMR cathode's structural integrity, a direct consequence of mitigated Mn dissolution. This work provides conclusive evidence that modulating bulk electrolyte solvation is a potent and direct strategy for stabilizing LMR cathodes, establishing a vital design principle for next-generation battery systems.

25 ENERGY STORAGE↗

Molten Lithium-Brass/Zinc Chloride System as High-Performance and Low-Cost Battery

Batteries with high safety, low cost, and reasonable energy density are essential for grid-scale energy storage and still remain elusive. In this paper, we report a solid electrolyte-based liquid lithium-brass/zinc chloride (SELL-brass/ZnCl 2 ) battery using garnet-type lithium-ion solid electrolyte, lithium anode, and brass/ZnCl 2 cathode. The chemistry of the cell reaction and the ability of being assembled in discharged state ensures a high safety. The use of low-cost ZnCl 2 cathode can realize a low cell material cost of $16 kWh –1 . The adoption of lithium anode guarantees a high theoretical energy density of 750 Wh kg –1 and 2,250 Wh L –1 . Moreover, by using brass powder as a Zn source in the cathode, the Zn particle growth issue is successfully solved, and a good cycling stability of the battery can be obtained. As full cell performance and scalability are also verified, our SELL-brass/ZnCl 2 battery shows a high potential for practical use in grid energy storage.

25 ENERGY STORAGE↗

Advances and perspectives of hard carbon anode modulated by defect/hetero elemental engineering for sodium ion batteries

Sodium-ion batteries (SIBs) serve as a promising complement to lithium-ion batteries for large-scale energy storage, leveraging the abundance of sodium resources and notable safety advantages. The key advancement in SIB industrialization hinges on identifying a cost-effective and high-performance anode material, similar to the graphite anode in lithium-ion batteries. Hard carbon emerges as prime anode materials for SIBs, boasting high specific capacity, low sodium storage potential, and wide availability. However, practical applications of hard carbon encounters challenges such as low initial Coulombic efficiency (ICE), inadequate long-term cycling stability, and poor rate performance. Recent research has focused on the optimization of hard carbon electrodes through functional design. In this comprehensive review, we have meticulously examined the progress in enhancing sodium storage performance through microstructural modulation within hard carbon, encompassing four pivotal aspects: heteroatom doping, incorporation of oxygen functional groups, surface coating, and intrinsic defect engineering. Progress in implementing these strategies is scrutinized, while the merits and challenges of each defect engineering approach are discussed. In conclusion, this review also looks into forthcoming opportunities and challenges in the practical application process of hard carbon electrodes in SIBs.

25 ENERGY STORAGE↗

Pd modified prussian blue frameworks: Multiple electron transfer pathways for improving catalytic activity toward hydrogenation of nitroaromatics

Prussian blue analogs (PBAs) exhibit potential as low-cost and eco-friendly nanocatalysts that can be fabricated with ease. However, the PBA framework structure suffers from poor electronic conductivity, which limits the catalytic efficiency for this class of materials. Noble metals represent an alternative class of materials that display inherent catalytic activity but suffer from aggregation, ultimately reducing the amount of accessible catalytic sites. Herein, we demonstrate a combinatory approach that circumvents the known disadvantages with these classes of catalytic materials in which PBA-supported nanocatalysts were synthesized. These composite materials exhibit excellent catalytic activity for the reduction of nitroaromatics to aminoaromatics while displaying long-term cycling stability, which is attributed to the availability of multiple electron transfer pathways. Overall, this work opens the study on the assembly of PBA-supported heterogeneous nanocatalysts and potentially paves the way toward future applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A case study of high-temperature polyetherimide film capacitor fabrication

Capacitors, as the basic building block of power electronics and electrical systems, are the major constraint of the increasingly integrated power systems that require new capable polymer dielectric films operating at higher temperatures >125 °C. Despite tremendous research efforts on the lab scale, there remains a considerable barrier and knowledge basis for converting polymeric films to functioning capacitors desired in actual applications. Here, the authors tackled the polyetherimide (PEI) film scale up issues and developed various engineering processes for film de-wrinkling, optimal metallization, static elimination, and capacitor fabrication improvement. The authors discovered various fabrication challenges such as the electrostatic charge, metallization scheme, winding tension, and end electrode disconnects. To fabricate a high yield of PEI capacitor bobbins, it is necessary to utilize static eliminators (radioactive ionizers), moderately thick aluminum metallization (15–30 Ω/sq), and winding tension (60–100 g). It is also effective to evaluate capacitance, dielectric loss, equivalent series resistance, and thermal cycling stability of capacitors. This work sheds some light on converting PEI films and other polymeric films to capacitors on a scale up fabrication effort. The practical learning from film handling to capacitor fabrication in this work provided the necessary knowledge for manufacturing high-temperature polar film capacitors.

36 MATERIALS SCIENCE↗

Petaloid-shaped ZnO coated carbon felt as a controllable host to construct hierarchical Li composite anode

Prestoring Li metal into the 3D host via thermal infusion strategy has been considered as an effective approach on suppressing Li dendrites growth of Li-metal anode during cycling. However, the fast Li infusing process generally induces uncontrollable and undesirable structures during the formation of composite Li metal anode. It is widely accepted that both physical and chemical interactions between the molten Li and the hosts provide driving forces for Li infusing into the host, but which one plays the dominant role has not been explored clearly. In this work, a 3D carbon felt coated by petaloid zinc oxide (CFZO) is designed as a controllable host for prestoring Li metal via thermal infusion method. It is revealed that the morphology induced physical driving force plays a more important role than the chemical reaction between ZnO and molten Li in the thermal infusion process. The physical driving force originates from the capillarity effect, depending on the roughness of the host according to Wenzel's model. An adjustable Li infusing process can be controlled to fabricate the Li composite electrode with a hierarchical structure (with dense Li-rich layer and porous Li-poor layer). The unique structure of the CFZO-Li not only provides enough spaces for Li deposition, but also disperses local current density to induce a uniform Li deposition behavior, thus Li dendrites can be suppressed effectively. As a result, CFZO-Li anode exhibits promising cycle stability when coupled with both Li-containing (LiNi 0.8 Co 0.15 Al 0.05 O 2 ) and Li-free (sulfur) cathodes.

25 ENERGY STORAGE↗

Sweeping potential regulated structural and chemical evolution of solid-electrolyte interphase on Cu and Li as revealed by cryo-TEM

A fundamental understanding of solid-electrolyte interphase (SEI) is paramount importance for controlling the cycling performance of rechargeable lithium metal batteries. The structural and chemical evolution of SEI with respect to electrochemical operating condition remains barely established. Here we develop a unique method for imaging the evolution of SEI formed on the Cu foil under sweeping electrochemical potential. By using cryogenic TEM imaging combined with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy electronic structure analyses, we reveal that, for the vinylene carbonate (VC)-free electrolyte, the SEI formed at 1.0 V is a monolithic amorphous structure, which evolves to amorphous matrix embedded with Li 2 O particles as the voltage decreases to 0 V. In the case of VC-containing electrolyte, the SEI is featured by an amorphous matrix with Li 2 O particles from 1.0 V to 0 V. The thickness of SEI formed on Cu foil increases with decreasing voltage. Associated with the localized charge modulation by the surface topographic feature and defects in the Cu foil, the SEI layer shows direct spatial correlation with these structural defects in the Cu. In addition, upon Li deposition, the SEI formed on the Li metal has similar thickness with, but different composition from the SEI formed on the Cu foil at 0 V. Furthermore, those results provide insight toward SEI engineering for enhanced cycling stability of Li metal.

25 ENERGY STORAGE↗

Regulating lithium deposition via electropolymerization of acrylonitrile in rechargeable lithium metal batteries

Here, we report acrylonitrile (AN) as an effective additive in carbonate-based electrolytes to enable uniform and dense lithium (Li) deposition and to improve the coulombic efficiency of Li metal anode. Our electrochemical, spectroscopic, and theoretical study reveal that AN is cathodically electropolymerized on the Li surface prior to the electrochemical decomposition of the electrolyte during Li deposition. The resultant polyacrylonitrile artificial solid electrolyte interphase enables uniform nucleation and growth of Li deposition with significantly reduced side reactions. The effectiveness of the AN additive is demonstrated in 0.4 Ah Li||LiNi 0.6 Mn 0.2 Co 0.2 O 2 pouch cells (using 50-μm Li anode, 3 mAh cm -2 cathode areal capacity, and 4g Ah -1 electrolyte) with excellent cycle stability under realistic charge-discharge condition

25 ENERGY STORAGE↗

Tunning the linkage of structure units to enable stable spinel-based cathode in the wide potential window

The low practical capacity (<140 mA h g –1 ) of spinel phase LiMn 2–x Ni x O 4 (0 < x < 1) excludes it from high energy density lithium ion batteries (LIBs) for powering electric vehicles. Extending the operating potential window from 3.0 to 4.8 V to 2.0–4.8 V can double the capacity, but result in fast capacity decay due to the drastic cubic-tetragonal phase transition below 3.0 V, induced by serious Jahn-Teller (J-T) distortion of structure units (Mn 3+ )O 6 octahedra. Herein, we propose a novel strategy to suppress J-T distortion by tuning the linkage of structure units MnO 6 octahedra. The original full-vertex-sharing LiO 4 tetrahedra around MnO 6 octahedra in spinel phase are partially replaced by edge-sharing LiO 6 octahedra, which relate Mn-O bonds along the dz 2 direction with those along the d xy plane, thus significantly mitigating J-T distortion and suppressing the phase transition when discharged to 2.0 V. Following this strategy, the prepared spinel-based cathode achieves a high reversible capacity of about 290 mA h g –1 and an energy density up to 957 W h kg –1 with improved cycling stability. Furthermore, this work finds a new opportunity for the traditional spinel cathode towards applications in high energy density LIBs in a low cost and sustainable manner.

25 ENERGY STORAGE↗

Heteroatom anchoring to enhance electrochemical reversibility for high-voltage P2-type oxide cathodes of sodium-ion batteries

P2-type cathode has received extensive attention due to its faster Na+ diffusion and a high theoretical capacity in sodium-ion batteries (SIBs). However, undesirable phase transformations have induced dramatic capacity decay of SIBs during the cycling process. In this study, heteroatom anchoring through Cu/Mg dual doping is introduced into P2-type Na 0.67 Ni 0.33 Mn 0.67 O 2 cathode to enhance high-voltage electrochemical reversibility and modulate interfacial Na + kinetics. Further, the as-prepared Na 0.67 Ni 0.23 Mg 0.05 Cu 0.05 Mn 0.67 O 2 exhibits an outstanding capacity retention (83.4% after 2000 cycles at 10C) and rate performance (73 mAh g -1 at 10C, accounting for 58.7% of that at 0.1 C) over the voltage range of 2.5–4.4 V. Intensive explorations further manifest that the modified mechanism of dual-ion doping strategy is attributed to the synergistic coupling effect of a substantial change in Na occupancy distribution and an increase in oxygen vacancy buffer. Thus, the optimized cathode expedites Na + diffusion and reduces detrimental phase transformation, which favors high-rate performance and long-term cycling stability. This study develops a route to rationally design high-voltage cathode materials for SIBs.

25 ENERGY STORAGE↗

Elucidating the Redox Behavior during Atomic Layer Deposition on Lithium-Ion Battery Cathode Materials

Atomic layer deposition (ALD) has emerged as a promising technology for applying ultrathin protective coatings on lithium-ion battery (LIB) cathode surfaces to improve their cycling stability. While there have been numerous reports evaluating the electrochemical performance of these surface-modified cathode materials, the chemical changes induced on the surface of the cathode materials upon ALD coating are not fully studied. This paper describes a systematic investigation to understand the interfacial changes of 12 different cathode materials upon coating with aluminum oxide (Al 2 O 3 ) using trimethyl aluminum (TMA) and H 2 O, and aluminum fluoride (AlF 3 ) using TMA and hydrogen fluoride pyridine (HFPy). Here, the surface composition of these cathode materials, which range from simple transition metal oxides (e.g. NiO and MnO) to complex multi-element cathode materials (e.g. LiNi x Mn 1-x-y Co y O 2 , NMC), was studied via X-ray photoelectron spectroscopy (XPS). The XPS measurements reveal that the transition metals in the cathode materials undergo selective oxidation/reduction depending upon the nature of the precursor, the coating, and the cathode material. The ability to chemically modify the surface of cathode materials via vapor-phase precursor adsorption will open new avenues to systematically control the interface of the cathode materials in LIBs that are not possible by conventional coating methods.

25 ENERGY STORAGE↗

Tin Metal Improves the Lithiation Kinetics of High-Capacity Silicon Anodes

Si-based anodes present a great promise for high energy density lithium-ion batteries. However, its commercialization is largely hindered by a grand challenge of a rapid capacity fade. Here, we demonstrate excellent cycling stability on a Si-Sn thin film electrode that outperforms pure Si or Sn counterpart under the similar conditions. Combined with the first-principles calculations, in situ transmission electron microscopy studies reveal a reduced volume expansion, increased conductivity, as well as dynamic rearrangement upon lithiation of the Si-Sn film. Here we attribute the improved lithiation kinetics to the formation of a conductive matrix that comprises a mosaic of nanostructured Sn, Li y Sn (specifically, Li 7 Sn 2 develops around the lithiation potential of Si), and Li x Si. This work provides an important advance in understanding the lithiation mechanism of Si-based anodes for next-generation lithium-ion batteries.

25 ENERGY STORAGE↗

Reversible Electrochemical Lithium Cycling in a Vanadium(IV)- and Niobium(V)-Based Wadsley–Roth Phase

Fast charging remains one of the greatest safety challenges in Li-ion batteries due to Li-dendrite growth occurring on graphite anodes if they are lithiated too quickly. The search for high-rate anodes has highlighted materials in the Wadsley–Roth (WR) shear phase family. The relative abundance of V compared with traditional WR compositions of Nb and W makes V-based phases attractive. However, the high voltage and poor reversibility typically associated with V redox have made V-rich WR phases less studied than Nb- and W-rich phases. Here, we show that a new V-rich Wadsley–Roth phase, V 7 Nb 6 O 29 , achieves excellent rate capability and 80% capacity retention after 228 cycles with a relatively low average voltage of 1.76 V vs Li/Li + compared with other V-rich WR phases. Single-crystal X-ray diffraction reveals a P4/m space group with repeating 2 × 2 × ∞ and 3 × 3 × ∞ blocks of V 4+ and Nb 5+ octahedra. Finally, combined neutron pair distribution function analysis, X-ray absorption spectroscopy, and density functional theory calculations show that V redox is the primary source of capacity and that cycling stability is provided by the stable octahedral coordination adopted by V 4+ in the material.

25 ENERGY STORAGE↗

Chloride Insertion Enhances the Electrochemical Oxidation of Iron Hydroxide Double-Layer Hydroxide into Oxyhydroxide in Alkaline Iron Batteries

Rechargeable alkaline iron batteries that constitute environmentally benign electrolytes and earth-abundant industrial materials are desirable green solutions for large-scale energy storage. As one of the most abundant metal elements in the earth’s crust, iron (Fe) can satisfy nearly all criteria for low-cost and safe battery electrodes. However, challenges in achieving reversible Fe redox impede their extensive implementation in modern energy supply systems. Here, this study revealed that Cl-anion insertion into Fe(OH) 2 layered double hydroxide (LDH) formed a green rust intermediate phase with the formula [Fe 2 2+ Fe 1 3+ (HO – ) 6 ] + [Cl] – , which assisted a high Fe(OH) 2 /FeOOH conversion reaction (64.7%) and improved cycling stability. This new iron redox chemistry was validated by operando X-ray diffraction, electrochemical testing, X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS) analysis, scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS) mapping, and molecular dynamics (MD) simulations. Our study provides new insight into designing LDH materials for high-capacity alkaline iron batteries.

36 MATERIALS SCIENCE↗