Binder-Free V2O5 Cathode for High Energy Density Rechargeable Aluminum-Ion Batteries.

Diem Diem,Burghard Burghard,Fenk Fenk,Bill Bill

doi:10.3390/nano10020247

Abstract

Nowadays, research on electrochemical storage systems moves into the direction of post-lithium-ion batteries, such as aluminum-ion batteries, and the exploration of suitable materials for such batteries. Vanadium pentoxide (V2O5) is one of the most promising host materials for the intercalation of multivalent ions. Here, we report on the fabrication of a binder-free and self-supporting V2O5 micrometer-thick paper-like electrode material and its use as the cathode for rechargeable aluminum-ion batteries. The electrical conductivity of the cathode was significantly improved by a novel in-situ and self-limiting copper migration approach into the V2O5 structure. This process takes advantage of the dissolution of Cu by the ionic liquid-based electrolyte, as well as the presence of two different accommodation sites in the nanostructured V2O5 available for aluminum-ions and the migrated Cu. Furthermore, the advanced nanostructured cathode delivered a specific discharge capacity of up to ~170 mAh g−1 and the reversible intercalation of Al3+ for more than 500 cycles with a high Coulomb efficiency reaching nearly 100%. The binder-free concept results in an energy density of 74 Wh kg−1, which shows improved energy density in comparison to the so far published V2O5-based cathodes. Our results provide valuable insights for the future design and development of novel binder-free and self-supporting electrodes for rechargeable multivalent metal-ion batteries associating a high energy density, cycling stability, safety and low cost.

Highlights

The rising demand for advanced energy storage systems, e.g., rechargeable metal‐ion batteries, with a high energy density requires novel electrode materials and fabrication concepts to fulfill crucial requirements for their application
Considering all aspects, the aforementioned limitations highlight the need for suitable cell design, which includes the optimal pairing of a current collector with an electrolyte, as well as the development of self‐supporting and binder‐free electrodes for aluminum‐ion batteries (AIBs)
Synthesis of V2O5 dispersion: The V2O5 nanofibers are synthesized by the mixing of ammonium meta‐vanadate (1 g, Fluka, Munich, Germany) and an acidic ion‐exchanger (10 g, Dowex 50WX8 50‐ 100, Alfa Aesar, Kandel, Germany) in deionized water (200 mL) [21], which is heated for 10 min in an 80 °C oil bath

Summary

Introduction

The rising demand for advanced energy storage systems, e.g., rechargeable metal‐ion batteries, with a high energy density requires novel electrode materials and fabrication concepts to fulfill crucial requirements for their application Those requirements include a high storage capacity and current density, as well as long‐term stability, low cost and sustainability [1,2,3]. While the working principle of rechargeable aluminum‐ion batteries (AIBs) has been clarified to some extent [8], the ongoing development faces several challenges This includes identifying suitable electrolytes, current collectors and additives. Ionic liquids, such as those imidazolium‐based, mixed with aluminum chloride (AlCl3) have shown some promise as electrolytes [10,11,12,13,14,15]. Considering all aspects, the aforementioned limitations highlight the need for suitable cell design, which includes the optimal pairing of a current collector with an electrolyte, as well as the development of self‐supporting and binder‐free electrodes for AIBs

Methods

Results

Conclusion