Work

Quasi-Commercial Pouch Sodium-Ion Battery Capacitors Achieve Extended High-Power Cyclability Through Na3V2(PO4)3/Activated Carbon Hybrid Cathode Design with Presodiation-Free Anodes

Year: 2025

Type: article

Abstract: Sodium–ion battery capacitors (SIBatCs) synergistically combine battery–type and capacitor–type components in an inter–parallel configuration, simultaneously delivering high energy and power densities. We pioneer the development of quasi–commercial pouch SIBatCs using Na3V2(PO4)3/activated carbon (NVP/AC) hybrid cathodes and hard carbon anodes. The hybrid design utilizes NVP as an intrinsic sodium source, eliminating complex anode presodiation—an obstacle to industrialization. The AC component fulfills multiple roles—contributing capacitive capacity, enhancing conductivity, and acting as an electrolyte reservoir, which decreases electrode resistivity as well as polarization. In full cells, an optimal NVP/AC mass ratio range of 10:1–2:1 is identified, enabling balanced low resistance, high energy density, exceptional power density, and long cycle life. SIBatCs incorporating R10/1 (mNVP:mAC = 10:1) and R4/1 (mNVP:mAC = 4:1) achieve energy densities of 148.9 Wh kg−1 (81.0 W kg−1) and 120.6 Wh kg−1 (79.3 W kg−1), respectively. Even at ultrahigh power densities of 30.53 and 29.81 kW kg−1, they retain corresponding energy densities of 50.4 and 39.6 Wh kg−1. They exhibit excellent capacity retentions of 32.8% and 41.6% after 5000 cycles—significantly outperforming pure NVP–based cells (18.0%). The hybrid architecture ensures robust performance across a wide temperature range (−30–60 °C). This work presents a scalable solution for high–performance sodium–ion EES hybrid systems.

Source: Batteries

DOI: 10.3390/batteries11100379