Electrode Engineering Study Toward High-Energy-Density Sodium-Ion Battery Fabrication

Abstract

Sodium-ion batteries (SIBs) are emerging as promising energy storage technologies, particularly for grid-scale applications, due to their low material costs stemming from abundant natural resources. Meeting the increasing demand for higher energy density requires the development of innovative electrode and electrolyte materials, along with advanced analytical and fabrication techniques. However, the energy density of SIBs is often evaluated based solely on the capacities and cell voltages of active materials in half-cell configurations, neglecting engineering considerations for full-cell configurations. This study investigates the effects of electrode composition and the balance in capacities between positive and negative electrodes (N/P ratio) on the performance of full-cell configurations, using Na3V2(PO4)3 (NVP) and hard carbon (HC) as representative electrode materials. Through a systematic analysis, an optimal composition for NVP and HC electrodes is proposed, considering areal capacity and capacity retention during full-cell operations. Additionally, the importance of balancing the N/P ratio and the necessity of presodiation techniques to achieve high-energy-density SIBs are underscored. Overall, this work sheds light on key factors influencing the performance of SIBs and provides insights into strategies for enhancing their energy density and operational efficiency.