An aluminium battery operating with an aqueous electrolyte

Abstract

Aluminium is an attractive active material for battery systems due to its abundance, low cost, a gravimetric energy density of 2.98 Ah g −1 (c.f. lithium 3.86 Ah g −1 ) and a volumetric energy density of 8.04 Ah cm −3 (c.f. lithium 2.06 Ah cm −3 ). An aqueous electrolyte-based aluminium-ion cell is described using TiO 2 nanopowder as the negative electrode, CuHCF (copper-hexacyanoferrate) as the positive electrode and an electrolyte consisting of 1 mol dm −3 AlCl 3 and 1 mol dm −3 KCl. Voltammetric and galvanostatic analyses have shown that the discharge voltage is circa 1.5 V. Both a single-cell and 2-cell battery are demonstrated using 10 cm 2 electrodes and 126 and 256 mg total active material for the 1-cell and 2-cell batteries, respectively. The single cell exhibits an energy density of circa 15 mW h g −1 (combined positive and negative electrode masses) at a power density of 300 mW g −1 with energy efficiency remaining above 70% for over 1750 cycles. Initial characterisation shows that charge storage is due to the presence of Al 3+ . Cell capacity is circa 10 mA h g −1 and operates with a discharge voltage of circa 1.5 V (efficiency > 80% at 20C charge/discharge rate). Graphical AbstractKeyword Aqueous aluminium ion battery

Water in Rechargeable Multivalent‐Ion Batteries: An Electrochemical Pandora's Box

“…Holland et al. initially found poor specific capacities for TiO 2 particles (actual 10 mAh g −1 vs. theoretical 335 mAh g −1 ), leading them to propose that the reaction TiO 2 + x Al 3+ +3 x e − ⇄Al x TiO 2 occurs only on surface sites . Lahan and Das later demonstrated this low specific capacity to be an artefact of poor electronic percolation within the active material, that is, they were able to achieve an enhanced capacity (52 mAh g −1 ) by compositing TiO 2 nanoparticles with conductivity‐enhancing graphite, and confirmed lattice changes to match with Al 2 TiO 5 and Al 2 Ti 7 O 15 phases through XRD and TEM analyses …”

“…On a per ion basis, this would be a charge vector superior to that of elemental lithium . Indeed, transposing concepts from the aqueous lithium system to other water‐based chemistries, recent reports have demonstrated remarkable breakthroughs with heavier elements, for example, Na, Mg, Al, K, Ca, Cu, Fe, Zn, Mn, Rb/Tl, and V . We aim to contribute insights to push these further, by focusing on low‐cost, multivalent‐ion (Mg, Ca, Zn, Al) battery development from an electrolyte point of view.…”

“…However, because stored electrochemical energy is released as ap roduct of voltage, current, and time, and the voltage stability of free water is severely limited, aqueous batteries inspire efforts to achieve high-energyb atteries by drastically increasing charge capacitya tm oderate voltages, rathert han by creating > 5V cell systems.One methodi st or eplacet he monovalent-ion shuttlew ith a multivalent-ion shuttle to effect multiple electron-transfer events per ion crossover.O naper ion basis, this would be a charge vector superior to that of elemental lithium. [7] Indeed, transposing concepts from the aqueous lithium system to other water-based chemistries, recent reports have demonstrated remarkable breakthroughs with heaviere lements, for example, Na, [8] Mg, [9] Al, [10] K, [11] Ca, [12] Cu, [13] Fe, [14] Zn, [15] Mn, [16] Rb/Tl, [17] and V. [18] We aim to contribute insights to push these [a] Dr.…”

The Compensation Effect Mechanism of Fe–Ni Mixed Prussian Blue Analogues in Aqueous Rechargeable Aluminum‐Ion Batteries

“…Recently, Gao and co‐workers reported that a type of copper‐hexacyanoferrate (CuHCF) has been synthesized, delivering a capacity of 41 mAh g −1 at 400 mA g −1 in 0.5 m Al 2 (SO 4 ) 3 aqueous electrolyte with acceptable capacity retention of 55 % after 1000 cycles . Wills and co‐workers also illustrated the availability of CuHCF as cathode material for aluminum‐ion batteries with an energy density of 15 mW h g −1 at a power density of 300 mW g −1 . Menke and co‐workers described CuHCF as a cathode material for aluminum‐ion batteries in an organic electrolyte, which delivered a reversible capacity of approximately 10 mA h g −1 at 50 μA cm −2 …”

Dendrite Growth Suppression by Zn2+‐Integrated Nafion Ionomer Membranes: Beyond Porous Separators toward Aqueous Zn/V2O5 Batteries with Extended Cycle Life

“…This has opened up new challenges as well as opportunities in the realization of more efficient aqueous ZIBs (AZIBs) with a variety of other cathode materials . Although other chemistries based on Al/Al 3+ and Mg/Mg 2+ have been proposed, the Zn/Zn 2+ systems are considered to be the leading candidate due to the high theoretical capacity (820 mAh g −1 ), low redox potential (−0.76 V vs standard hydrogen electrode [SHE]), natural abundance, and low cost of Zn metal …”