Work

Ultrafast Chemical Pre‐Sodiation of Pseudocapacitive CaV 8 O 20 Anodes for High‐Performance Sodium‐Ion Capacitors

Year: 2026

Type: article

Abstract: ABSTRACT The practical implementation of sodium‐ion capacitors (SICs) is impeded by structural degradation of anode materials and irreversible depletion of active sodium during initial solid‐electrolyte interphase formation. Herein, we propose a synergistic design paradigm that combines a structurally robust calcium vanadate (CaV 8 O 20 ) anode with a gas‐free, scalable chemical pre‐sodiation approach. Driven by the “spectator effect” of Ca 2+ pillars, the pseudocapacitive CaV 8 O 20 framework enables highly reversible, quasi‐zero‐strain Na + transport, ensuring 90% capacity retention after 600 cycles in half‐cells. To overcome the initial active sodium losses, a rapid roll‐to‐roll chemical pre‐sodiation utilizing a highly reducing Na‐benzophenone solution is employed, yielding nearly 100% coulombic efficiency within just 2 min. Consequently, the pre‐sodiated full‐cell SIC delivers an exceptional specific energy of 176 Wh kg −1 and specific power of 380 W kg −1 , alongside an outstanding lifespan of 10,000 cycles (87% retention). Coupled with stepwise operando electrochemical impedance spectroscopy to elucidate diffusion kinetics, this work establishes a scalable pathway to ultrastable, high‐performance SICs.

Source: Advanced Science

DOI: 10.1002/advs.77176