Unlocking the Potential of 2D MoS2 Cathodes for High-Performance Aqueous Al-Ion Batteries: Deciphering the Intercalation Mechanisms

In recent years, there have been significant advancements in Al-ion battery development, resulting in high voltage and capacity. Traditionally, only carbon-based materials with layered structures and strong bonding capabilities can deliver superior performance. However, most other materials exhibited low discharge voltages of 1.4 V, especially in aqueous Al-ion battery systems lacking anion intercalation. Thus, the development of high-voltage cathode materials has become crucial. This study introduces 2D MoS2 as a high-performance cathode for aqueous Al-ion batteries. The material's interlayer structure enables the intercalation of AlCl4 - anions, resulting in high-voltage intercalation. The resulting battery achieved a high voltage of 1.8 V with a capacity of 750 mAh g-1 , contributing to a high energy density of 890 Wh kg-1 and an impressive retention rate of ≈100% after 200 cycles. This research not only sheds light on the high-voltage anion-intercalation mechanism of MoS2 but also paves the way for the further development of advanced cathode materials in the field of Al-ion batteries. By demonstrating the potential of using 2D MoS2 as a cathode material, this finding can lead to the development of more efficient and innovative energy storage technologies, ultimately contributing to a sustainable and green energy future.

Multi-ion Strategy toward Highly Durable Calcium/Sodium-Sulfur Hybrid Battery

Nonlithium (Li) metal-sulfur batteries are a viable technology for large-scale energy storage due to their relative high energy densities and low cost. However, their practical application is still hindered by the insufficient reversibility and/or limited cycling stability. Herein, we report a high-performance calcium/sodium-sulfur (Ca/Na-S) hybrid battery enabled by a multi-ion chemistry. The introduction of Na ions in the electrolyte greatly boosts the conversion of Ca polysulfides, which has been verified by theoretical calculation and experimental investigation. Meanwhile, the presence of Ca ions constructs a protective electrostatic shield around the initial protrusions on the Na metal anode without prereduction, thus efficiently suppressing the Na dendrite growth. The as-developed Ca/Na-S cell exhibited a high reversible capacity of 947 mAh g^-1 at 0.1 C with long cycle life, clearly demonstrating the feasibility of this multi-ion strategy for developing low-cost non-Li metal-sulfur batteries.

A Multi-Ion Strategy towards Rechargeable Sodium-Ion Full Batteries with High Working Voltage and Rate Capability

Sodium-ion batteries (SIBs) are a promising alternative for the large-scale energy storage owing to the natural abundance of sodium. However, the practical application of SIBs is still hindered by the low working voltage, poor rate performance, and insufficient cycling stability. A sodium-ion based full battery using a multi-ion design is now presented. The optimized full batteries delivered a high working voltage of about 4.0 V, which is the best result of reported sodium-ion full batteries. Moreover, this multi-ion battery exhibited good rate performance up to 30 C and a high capacity retention of 95 % over 500 cycles at 5 C. Although the electrochemical performance of this multi-ion battery may be further enhanced via optimizing electrolyte and electrode materials for example, the results presented clearly indicate the feasibility of this multi-ion strategy to improve the electrochemical performance of SIBs for possible energy storage applications.