Enhancing the Whole Migration Kinetics of Na⁺ in the Anode Side for Advanced Ultralow Temperature Sodium‐Ion Hybrid Capacitor

Abstract

Boosting the ultralow temperature (below −30 °C) performance of Na‐ion hybrid capacitors (SIHCs), which integrate the high energy density of batteries with the high output power and long life of supercapacitors, is critical for the application of advanced electronics in extreme environments. However, their low‐temperature performance, especially fast charging capability, is hindered by difficult desolvation and slow pass solid electrolyte interphase (SEI) together with sluggish diffusion within the electrode. Herein, a “single‐solute–single‐solvent” electrolyte is developed and a through‐hole hollow carbon sphere (TH‐HCS) is constructed, and it is demonstrated through theoretical calculations and experimental investigations that the weakly solvated structure and high ionic conductivity facilitate the Na+ transportation at low temperatures, the highly fluorinated SEI facilitates the Na+ migration, and the through‐hole hollow structure alleviates the volume expansion during sodiation, thus ensuring fast kinetics and structural stability. As expected, TH‐HCS using this electrolyte exhibits a high specific capacity of 87.5 mAh g−1 after 11 000 cycles at 1.0 A g−1 and −40 °C. Coupled with activated carbon, the assembled SIHC displays an energy density of 106.1 and 52.0 Wh kg−1 at 25 and −40 °C, respectively, far exceeding the performance of commercial energy storage systems at low temperature.

Tailoring composite gel polymer electrolytes with regularly arranged pores and silica particles for sodium metal batteries via breath-figure self-assembly

“…55,56 This hybrid layer could be formed due to the suppressed decomposition of ethylene carbonate (EC) and diethyl carbonate (DEC), and it was related to the Na + -coordination state with the carbonate solvents. 57 As shown in Raman spectra in Fig. S17,† the electrolyte-wetted P-P3S7 displays a higher fraction of free EC/DEC than those of GF.…”

Dual surface/bulk engineering of Nb2O5 for high‐rate sodium storage

“…Sodium-ion capacitors (SICs) have gained significant attention in recent years due to their fast-charging capabilities, low cost, and availability of raw materials. [1][2][3][4][5][6][7][8][9][10][11][12] Orthorhombic Nb 2 O 5 (T-Nb 2 O 5 ) is a pseudocapacitive material that holds great promise as a high-rate anode for sodium storage. [13][14][15][16] However, the low electronic conductivity of T-Nb 2 O 5 remains a significant challenge, and current research efforts are primarily focused on improving its conductivity at the surface and bulk levels.…”