Rechargeable Potassium‐Ion Full Cells Operating at −40 °C

Abstract

Potassium‐ion batteries (PIBs) are promising for cryogenic energy storage. However, current researches on low‐temperature PIBs are limited to half cells utilizing potassium metal as an anode, and realizing rechargeable full cells is challenged by lacking viable anode materials and compatible electrolytes. Herein, a hard carbon (HC)‐based low‐temperature potassium‐ion full cell is successfully fabricated for the first time. Experimental evidence and theoretical analysis revealed that potassium storage behaviors of HC anodes in the matched low‐temperature electrolyte involve defect adsorption, interlayer co‐intercalation, and nanopore filling. Notably, these unique potassiation processes exhibited low interfacial resistances and small reaction activation energies, enabling an excellent cycling performance of HC with a capacity of 175 mAh g−1 at −40 °C (68 % of its room‐temperature capacity). Consequently, the HC‐based full cells demonstrated impressive rechargeability and high energy density above 100 Wh kg−1cathode at −40 °C, representing a significant advancement in the development of PIBs.

Selective Lattice Doping Enables a Low‐Cost, High‐Capacity and Long‐Lasting Potassium Layered Oxide Cathode for Potassium and Sodium Storage

“…In the spectrum, the semicircle in the highfrequency region corresponds to the formation of solid electrolyte interface film (R f ), and the semicircle in the mediumfrequency region is attributed to the charge transfer (R ct ) process at the electrode-electrolyte interface. [29] The KMO electrode exhibits the largest impedance at OCV, indicative of the rapid growth of surface films and poor kinetic properties. In comparison, the KCFMO electrode shows the lowest resistance, accounting for its excellent rate performance.…”

Electrolytes Design for Extending the Temperature Adaptability of Lithium‐Ion Batteries: from Fundamentals to Strategies

“…Establishing the correlation between solvation structure and electrochemical properties, as well as obtaining effective strategies to adjust solvation behavior, is crucial for electrolyte design. In comparison with SIBs, potassium ions possess a smaller Stoke radius and weaker solvation effect, enabling them to exhibit rapid migration and desolvation ability, [251][252][253][254] thereby presenting the potential for LT energy storage. Therefore, the extension of the LT lithium electrolyte strategy to potassium ion batteries (PIBs) is promising for their implementation.…”

Conductive Polymer-Based Interlayers in Restraining the Polysulfide Shuttle of Lithium–Sulfur Batteries

“…Advanced in situ characterization techniques should be employed to investigate the detailed working mechanisms in order to further modify the interlayer. Finally, the influence of conductive polymer interlayers on the low-temperature performance of LSBs should be carefully evaluated [ 89 , 90 , 91 ].…”