Electronic Cloud Topology-Driven Electrostatic Decoupling: To Suppress High-Voltage Parasitic Reactions of Phosphate Cathode in Sodium-Ion Batteries.

The polyanionic structure cathodes with synergistic Mn/V redox couples enables high-voltage platform and delivers considerable theoretical energy density in sodium-ion battery. However, achieving stable and reversible high-voltage redox reactions remain challenging due to the inactivation of redox couples during discharge. Herein, we found that coupled redox behavior triggered by orbitals with similar energy levels leads to high-voltage irreversibility and parasitic reactions.

Durable Potassium Storage Achieved by Boron Coordination in a P2-Type Layered Oxide Skeleton.

Layered transition-metal (TM) oxides are of high application value as a cathode for potassium (K)-ion batteries toward high energy density. However, the inadequate covalency of the TM-O bond inevitably induces TM migration and subsequent irreversible structural transformation upon operating, which results in poor rate and long cycle reliability. To address this issue, we employed boron coordination chemistry to manipulate the local electronic structure in a prototype P2-layered KMnNiBO (KMNBO).

Heterogeneous-Interface-Induced Charge Redistribution Toward Fe-Based Polyanion Cathode for Advanced Sodium-Ion Batteries.

NaFe(PO)PO (NFPP) is gradually developing into one of the most commercially prospective cathode materials for sodium-ion batteries. However, the inactive phase maricite-NaFePO (m-NFP) normally tends to be formed during the synthesis process of NFPP, as well as the intrinsic poor electronic conductivity, which impacts the realization of high Na-storage performance. Herein, for the first time, we have constructed a heterostructure in Fe-based polyanionic cathode materials by fine-tuning the stoichiometric ratio of the Na site; the inactive phase m-NFP is fully transformed to the active NaFePO or NFPP.

Breaking Anionic Solvation Barrier for Safe and Durable Potassium-ion Batteries Under Ultrahigh-Voltage Operation.

Ultrahigh-voltage potassium-ion batteries (PIBs) with cost competitiveness represent a viable route towards high energy battery systems. Nevertheless, rapid capacity decay with poor Coulombic efficiencies remains intractable, mainly attributed to interfacial instability from aggressive potassium metal anodes and cathodes. Additionally, high reactivity of K metal and flammable electrolytes pose severe safety hazards.

Defect engineering unveiled: Enhancing potassium storage in expanded graphite anode.

Expanded graphite (EG) stands out as a promising material for the negative electrode in potassium-ion batteries. However, its full potential is hindered by the limited diffusion pathway and storage sites for potassium ions, restricting the improvement of its electrochemical performance. To overcome this challenge, defect engineering emerges as a highly effective strategy to enhance the adsorption and reaction kinetics of potassium ions on electrode materials.

High-Rate and Long-Cycle Cathode for Sodium-Ion Batteries: Enhanced Electrode Stability and Kinetics via Binder Adjustment.

Sodium-ion batteries (SIBs) are heralded as promising candidates for grid-scale energy storage systems due to their low cost and abundant sodium resources. Excellent rate capacity and outstanding cycling stability are always the goals for SIBs. Up to now, nearly all attention has been focused on the control of morphology and structure of electrode materials, but the influence of binders on their performance is neglected, especially in cathode materials.