Dual‐Function Presodiation with Sodium Diphenyl Ketone towards Ultra‐stable Hard Carbon Anodes for Sodium‐Ion Batteries

Abstract

Hard carbon (HC) is a promising anode material for sodium‐ion batteries, yet still suffers from low initial Coulombic efficiency (ICE) and unstable solid electrolyte interphase (SEI). Herein, sodium diphenyl ketone (Na‐DK) is applied to realize dual‐function presodiation for HC anodes. It compensates the irreversible Na uptake at the oxygen‐containing functional groups and reacts with carbon defects of five/seven‐membered rings for quasi‐metallic sodium in HC. The as‐formed sodium induces robust NaF‐rich SEI on HC in 1.0 M NaPF6 in diglyme, favoring the interfacial reaction kinetics and stable Na+ insertion and extraction. This renders the presodiated HC (pHC) with high ICE of ≈100 % and capacity retention of 82.4 % after 6800 cycles. It is demonstrated to couple with Na3V2(PO4)3 cathodes in full cells to show high capacity retention of ≈100 % after 700 cycles. This work provides in‐depth understanding of chemical presodiation and a new strategy for highly stable sodium‐ion batteries.

Chemical Prepotassiation Realizes Scalable KC8Foil Anodes for Potassium‐Ion Pouch Cells

“…From the above analysis, we can adjust the kinetics and thermodynamics of prepotassiation reaction through the coordination chemistry of (DMBP) n ‐K complexes, which is completely different from previously reported strategies based on the type and property of organic solvents and radical anions. [ 41,42,54–58 ]…”

“…From the above analysis, we can adjust the kinetics and thermodynamics of prepotassiation reaction through the coordination chemistry of (DMBP) n -K complexes, which is completely different from previously reported strategies based on the type and property of organic solvents and radical anions. [41,42,[54][55][56][57][58] Moreover, the electrochemical properties of KC 8 anodes were studied. To improve the cycling stability of the KC 8 electrode without solvent co-intercalation, 3 m potassium-bis (fluorosulfonyl)imide in dimethoxyethane was selected as the electrolyte.…”

Metal‐Organic Assembly Strategy for the Synthesis of Layered Metal Chalcogenide Anodes for Na+/K+‐Ion Batteries

“…For the practical application, the ICE should be paid special attention to improve the electrochemical performance of the full cells. In the previous studies, some strategies including electrochemical presodiation, chemical addition of sodium source, direct contact with the Na metal, have been reported, which can effectively increase the ICE [188,189] . However, the involved technics are complex and time‐consuming, it is a challenge for the large‐scale operation.…”

Unlocking fast and highly reversible sodium storage in Fe-based mixed polyanion cathodes for low-cost and high-performance sodium-ion batteries

“…[1][2][3][4] In particular, sodium-ion batteries (SIBs) have been widely investigated for large-scale energy storage applications on account of the low cost, abundant, and globally distributed sodium resources. [5][6][7][8][9] Cathode materials contribute much to the battery cost and have become the bottleneck of SIBs due to the great progress in anode materials (mostly in hard carbon [10][11][12] ). In this regard, of signicant promise are cost-effective, high-capacity, long life, and stable cathodes so as to improve SIBs.…”