Lithium-free Al-graphite-dual-ion batteries (AGDIB) have gained much attention due to their low-cost and sustainability. Commercial Al-foils and natural graphite are employed as electrode materials, ionic liquids such as AlCl3/[EMIm]Cl as anolyte. Al2Cl7– and AlCl4– within the anolyte are responsible for Al dissolution and plating, whereas AlCl4– is (de)intercalated between layers of graphite. While offering a moderate energy density, rate capability (20 A/gGraphite), power density (9,000 W/kgGraphite) and cycling stability (N > 500,000) are enormous. AGDIBs as high-power batteries fill the gap between supercapacitors and established (high-energy) battery types. Using an AlCl3/urea anolyte yields acceptable battery performance at even further reduced costs. With the aim of moving towards battery application, several challenges have to be met: use-cases have to be examined, and a cell design has to be developed which is resistant towards the corrosive electrolyte.
Chronoamperometry was employed to examine possible use cases and revealed a very strong relative power response to the potential pulse which is needed to stabilize grid microcycles for instantaneous reserve. Thus, AGDIB meet the highly dynamical requirements necessary for grid stabilization and provide a promising low cost and high-power energy-storage system suitable for further stationary and hybrid mobile applications.
The electrolyte’s corrosivity can be tackled by carefully choosing suitable casing materials allowing for long-term stable and application-oriented pouch cells showing similar properties as lab test cells. In addition, electrode manufacturing was optimized, e.g. with respect to binder materials and conductive additives of the water based slurries. Post-mortem microscopic methods were employed to analyse material stability of active and passive components upon cycling. The thus revealed causes for battery failure allow for further optimization of AGDIB pouch cells.