Phase Transition during Sintering of Layered Transition Metal Oxide Sodium Cathodes.

Layered cathodes derived from precursor materials have garnered significant attention in sodium ion battery (SIB) research. However, the structure evolution mechanisms during the sintering process remain inadequately understood. In this work, two precursors with irregular and regular morphologies were subjected to identical calcination conditions to synthesize O3-NaNiFeMnO cathodes.

Constraining Interlayer Slipping in P2-Type Layered Oxides with Oxygen Redox by Constructing Strong Covalent Bonds.

Lattice oxygen redox (LOR) in P2-type layered oxides is an effective strategy to break through the limit of energy density of conventional cathodes due to its high redox potential (>4 V vs Na/Na) as well as extra capacity. Nevertheless, LOR-induced local structure distortion and irreversible phase transitions cause serious electrochemical performance degradation, hindering practical applications. Herein, we propose that the generation of the OP4 phase can be replaced with the Z phase by introducing the Sb element with a higher ionic potential and strong covalent bonds within the TMO octahedron.

Coupling active and inactive transition metals to boost calcium storage cycle stability for Prussian blue cathodes.

Due to the advantages of resource abundance and low reduction potential of calcium, calcium-ion battery (CIB) becomes one of the potential candidates for energy storage devices. Prussian blue analogues (PBAs) are promising cathode materials for CIB, but they suffer from limited capacity and poor cyclability. Herein, a new PBA cathode NiCoHCF is designed with electrochemical active Co and inactive Ni.

Air stable and fast-charging cathode material for all climate sodium-ion batteries.

The off-stoichiometric compound NaFe(PO) (NFPO) is a highly promising, cost-effective, and structurally robust cathode material for sodium-ion batteries (SIBs). However, the slowing Na-ion migration kinetics and poor interface stability have seriously limited its rate capability and air stability. In this work, we successfully synthesis a sodium titanium pyrophosphate (NaTiPO donated as NTPO) coating NFPO (denoted as NFPO-NTPO) cathode material via a liquid phase coating method for SIBs.

Tetrahedral Occupied V Ions Enabling Reversible Three-Electron Redox of Cr /Cr in Layered Cathode Materials for Potassium-Ion Batteries.

Reversible three-electron redox of Cr /Cr in layered cathode materials for rechargeable batteries is very attractive in layered cathode materials, which leads to high capacity and energy density for rechargeable batteries. However, the poor reversibility and Cr-ion migration make it very challenging. In this work, by introducing V ions into tetrahedral sites of layer-structured NaCrO , reversible three-electron redox of Cr /Cr is realized successfully in NaCr V O (NCV05) cathode for potassium-ion batteries with a cut-off voltage of 4.

Stacking Order Induced Anion Redox Regulation for Layer-Structured Na Li Mn Cu O Cathode Materials.

Stacking order plays a key role in defining the electrochemical behavior and structural stability of layer-structured cathode materials. However, the detailed effects of stacking order on anionic redox in layer-structured cathode materials have not been investigated specifically and are still unrevealed. Herein, two layered cathodes with the same chemical formula but different stacking orders: P2-Na Li Mn Cu O (P2-LMC) and P3-Na Li Mn Cu O (P3-LMC) are compared.

Transition Metal Vacancy in Layered Cathode Materials for Sodium-Ion Batteries.

Anionic redox has been considered as a promising strategy to break the capacity limitation of cathode materials that solely relies on the intrinsic cationic redox in secondary batteries. Vacancy, as a kind of defect, can be introduced into transition metal layer to trigger oxygen redox, thus enhancing the energy density of layer-structured cathode materials for sodium-ion batteries. Herein, the formation process, recent progress in working mechanisms of triggering oxygen redox, as well as advanced characterization techniques for transition metal (TM) vacancy were overviewed and discussed.

Pilot-Scale Synthesis Sodium Iron Fluorophosphate Cathode with High Tap Density for a Sodium Pouch Cell.

Sodium-ion batteries (SIBs) have attracted wide interest for energy storage because of the sufficient sodium element reserve on the earth; however, the electrochemical performance of SIBs cannot achieve the requirements so far, especially, the limitation of cathode materials. Here, a kilogram-scale route to synthesize Na FePO F/carbon/multi-walled carbon nanotubes microspheres (NFPF@C@MCNTs) composite with a high tap density of 1.2 g cm is reported.

The Raw Mixed Conducting Interphase Affords Effective Prelithiation in Working Batteries.

Contact prelithiation is an important strategy to compensate the initial capacity loss of lithium-ion batteries. However, the dead Li generated from inadequate Li conversion reduces the cycling stability of rechargeable batteries. Herein a mono-solvent dimethyl carbonate (DMC) electrolyte was employed in contact prelithiation for the first time.

Anomalous Redox Features Induced by Strong Covalency in Layered NaTi V S Cathodes for Na-Ion Batteries.

The rising demand for energy density of cathodes means the need to raise the voltage or capacity of cathodes. Transition metal (TM) doping has been employed to enhance the electrochemical properties in multiple aspects. The redox voltage of doped cathodes usually falls in between the voltage of undoped layered cathodes.

Anionic Redox Regulated via Metal-Ligand Combinations in Layered Sulfides.

The increasing demand for energy storage is calling for improvements in cathode performance. In traditional layered cathodes, the higher energy of the metal 3d over the O 2p orbital results in one-band cationic redox; capacity solely from cations cannot meet the needs for higher energy density. Emerging anionic redox chemistry is promising to access higher capacity.

Stabilizing Transition Metal Vacancy Induced Oxygen Redox by Co /Co Redox and Sodium-Site Doping for Layered Cathode Materials.

Anionic redox is an effective way to boost the energy density of layer-structured metal-oxide cathodes for rechargeable batteries. However, inherent rigid nature of the TMO (TM: transition metals) subunits in the layered materials makes it hardly tolerate the inner strains induced by lattice glide, especially at high voltage. Herein, P2-Na Mg [Mn Co Mg □ ]O (□: TM vacancy) is designed that contains vacancies in TM sites, and Mg ions in both TM and sodium sites.

Boosting Reversibility of Mn-Based Tunnel-Structured Cathode Materials for Sodium-Ion Batteries by Magnesium Substitution.

Electrochemical irreversibility and sluggish mobility of Na in the cathode materials result in poor cycle stability and rate capability for sodium-ion batteries. Herein, a new strategy of introducing Mg ions into the hinging sites of Mn-based tunnel-structured cathode material is designed. Highly reversible electrochemical reaction and phase transition in this cathode are realized.

Freestanding Double-Layer MoO/CNT@S Membrane: A Promising Flexible Cathode for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries have been regarded as a promising candidate of secondary batteries to satisfy the enormous demand for electric vehicles and energy storage applications. However, Li-S batteries still suffer from severe capacity fading due to the shuttle effect of lithium polysulfides. Here, we develop a freestanding double-layer MoO/carbon nanotube@S (FMC@S) membrane by hydrothermal and suction filtration strategy, without polymer binder and current collector substrate.

Improving the Electrochemical Performance and Structural Stability of the LiNiCoAlO Cathode Material at High-Voltage Charging through Ti Substitution.

LiNiCoAlO (NCA) has been proven to be a good cathode material for lithium-ion batteries (LIBs), especially in electric vehicle applications. However, further elevating energy density of NCA is very challenging. Increasing the charging voltage of NCA is an effective method, but its structural instability remains a problem.