Reducing Structural Distortion by Tailoring Orbital Interactions in High-Voltage Polyanionic Cathodes.

The structural distortion of electrode materials in battery systems usually results in the structure degradation and capacity fading upon cycling. However, the fundamental mechanism about the structural distortion remains elusive. A critical issue has emerged concerning the utilization of high-voltage potassium vanadium fluorophosphate compound (KVPOF) as a competitive cathode material for potassium-ion battery applications.

Synergistically competitive coordination for tailoring sodium cointercalation potential of graphite.

Sodium co-intercalation in graphite negative electrodes delivers high-rate kinetics, and yet its implementation is plagued by notorious reaction potential. While prior efforts reduce the co-intercalation potential, the design remains limited by the intrinsic properties of electrolyte. Herein, a flexible design strategy based on synergistically competitive coordination is developed to tailor co-intercalation potential in dilute ether systems.

Investigating K Storage Behavior of Highly Graphitized Carbon Fibers as Anodes for a Potassium-Ion Battery.

Many problems of potassium-ion batteries (PIBs) are hidden under a low mass load of the active material. However, developing research based on areal capacity is challenging for PIBs, due to the lack of an anode capable of delivering a stable capacity of more than 1 mAh cm. This work investigates the K storage behavior of highly graphitized carbon fibers (HG-CF), which exhibit automatic structural adjustments to mitigate voltage polarization.

Key Factor Determining the Cyclic Stability of the Graphite Anode in Potassium-Ion Batteries.

Graphite is the most commonly used anode material for not only commercialized lithium-ion batteries (LIBs) but also the emerging potassium-ion batteries (PIBs). However, the graphite anode in PIBs using traditional dilute ester-based electrolyte systems shows obvious capacity fading, which is in contrast with the extraordinary cyclic stability in LIBs. More interestingly, the graphite in concentrated electrolytes for PIBs exhibits outstanding cyclic stability.

Polyvinylpyrrolidone-Bridged Prussian Blue/rGO Composite as a High-Performance Cathode for K-Ion Batteries.

Prussian blue (PB) is a very promising cathode for K-ion batteries but its low electronic conductivity and deficiencies in the framework aggravate electrochemical performances. Compositing with conductive reduced graphene oxide (rGO) is an effective solution to address this problem. Nevertheless, little attention was paid to the loss of oxygen-containing functional groups on the rGO substrate during the compositing process, which weakens the interaction between PB and rGO and leads to poor electrochemical performance of PB/rGO.