Tunable Interfacial Electric Field‐Mediated Cobalt‐Doped FeSe/Fe₃Se₄ Heterostructure for High‐Efficiency Potassium Storage

Abstract

The interfacial electric field (IEF) in the heterostructure can accelerate electron transport and ion migration, thereby enhancing the electrochemical performance of potassium‐ion batteries (PIBs). Nevertheless, the quantification and modulation of the IEF for high‐efficiency PIB anodes currently remains a blank slate. Herein, we achieve for the first time the quantification and tuning of IEF via amorphous carbon‐coated undifferentiated cobalt‐doped FeSe/Fe3Se4 heterostructure (denoted UN‐CoFe4Se5/C) for efficient potassium storage. Co doping can increase the IEF in FeSe/Fe3Se4, thereby improving the electron transport, promoting the potassium adsorption capacity, and lowering the diffusion barrier. As expected, the IEF magnitude in UN‐CoFe4Se5/C is experimentally quantified as 62.84 mV, which is 3.65 times larger than that of amorphous carbon‐coated FeSe/Fe3Se4 heterostructure (Fe4Se5/C). Benefiting from the strong IEF, UN‐CoFe4Se5/C as a PIB anode exhibits superior rate capability (145.8 mAh g−1 at 10.0 A g−1) and long cycle lifespan (capacity retention of 95.1% over 3000 cycles at 1.0 A g−1). Furthermore, this undifferentiated doping strategy can universally regulate the IEF magnitude in CoSe2/Co9Se8 and FeS2/Fe7S8 heterostructures. This work can provide fundamental insights into the design of advanced PIB electrodes.

Mini-Review on Organic Electrode Materials: Recent Breakthroughs and Advancement in Metal Ion Batteries

“…To date, metal oxide-based inorganic electrode materials continue to be widely explored and utilized in Li-, Na-, and K-ion batteries. − OEMs being inexpensive, recyclable, safe, and electrochemically reversible have shown great potential as promising materials for energy storage and conversion. The various advantages and applications of OEMs are summarized in Table .…”

Encapsulating Selenium into Biomass-Derived Nitrogen-Doped Porous Carbon As the Cathode for Sodium–Selenium and Potassium–Selenium Batteries

“…1−3 Sodium/potassium−selenium (Na/K−Se) batteries are promising for their potential in stationary energy storage technology owing to their high theoretical capacity, abundant availability of sodium/potassium, and lower cost. 4,5 Moreover, the Se cathode exhibits high-rate performance due to its superior intrinsic conductivity (∼10 −3 S m −1 ) compared to sulfur congener. 6 However, the practical implementation of Na/K−Se batteries has been hindered by several bottlenecks, including inadequate utilization of Se, the intermediate polyselenide shuttling, and significant volume expansion (∼400%) upon cycling.…”

“…Rechargeable lithium-ion batteries have been extensively employed in portable electronics and electrified transportation in the past decades. However, the high cost of lithium salts and mediocre energy density have prompted a search for alternative technologies. − Sodium/potassium–selenium (Na/K–Se) batteries are promising for their potential in stationary energy storage technology owing to their high theoretical capacity, abundant availability of sodium/potassium, and lower cost. , Moreover, the Se cathode exhibits high-rate performance due to its superior intrinsic conductivity (∼10 –3 S m –1 ) compared to sulfur congener . However, the practical implementation of Na/K–Se batteries has been hindered by several bottlenecks, including inadequate utilization of Se, the intermediate polyselenide shuttling, and significant volume expansion (∼400%) upon cycling. − Therefore, it is imperative to devise effective strategies for stabilizing Se cathodes and enhancing the Na/K storage performance in order to advance the development of Na/K–Se systems.…”

Hollow Defect-Rich Nanofibers as Sulfur Hosts for Lithium–Sulfur Batteries

“…With the rapid development of the new energy industry, various types of new secondary batteries have been widely studied. − Among these, lithium–sulfur (Li–S) batteries, as a high energy density (2600 Wh kg –1 ) battery, have triggered a wide range of research. − As a multielectron transfer reaction, sulfur cathode is capable of releasing a high discharge specific capacity of 1675 mAh g –1 under ideal conditions, and at the same time, lithium–sulfur batteries combine the advantages of low cost and environmental friendliness. − However, the commercial application of lithium–sulfur batteries still faces a series of challenges. − The poor electrical conductivity of the active substance sulfur (S) and the final discharge product lithium sulfide (Li 2 S), the huge volume expansion during charging and discharging due to the different densities of S and Li 2 S, as well as the shuttle effect due to the dissolution of soluble intermediate lithium polysulfides (LiPSs) during the reaction process have seriously hindered the commercialization of lithium–sulfur batteries. − …”