Paloma Almodovar

Title : Dimensionality of MnO2 cathodes as a key factor governing kinetics in Alumninium-ion batteries

Abstract:

Along with the non-stopping technological expansion, modern societies are in need of a constant energetic supply. Equipment with a stationary and non-stationary objective must have battery or capacitor devices adapted to its requirements, where energy storage has to be efficient. The Lithium-ion technology remains the most demanded system. However, the high cost and limited amount of lithium available has led to research for alternative systems: Na, K, Mg, Al, Ca and Zn [1]. One of the most promising alternative among next-generation energy storage system is the aluminium-ion battery (AIB) which has a higher theoretical volumetric (8046 mA h cm^-3) and gravimetric (2980 mA h g^-1) capacity, but also due to its low cost, sustainability and low flammability [2,3].

Electrochemical activity of different MnO₂ phases as electrodes of aluminium-ion batteries (AIBs) is studied. For this purpose, different simple synthesis routes have been carried out to obtain on the one hand, MnO₂ rod-like with tunnelled structure (α-MnO₂) and on the other MnO₂ hexagonal micro-pellets with lamellar structure (δ-MnO₂). α-MnO₂ showed an outstanding capacity (Q) of 120 mA h g^-1 at current densities of 100 mA g^-1, which remains stable after 100 cycles with efficiencies over 90%.  δ-MnO₂ showed a good capacity of 80 mA h g^-1 at current densities of 50 mA g^-1 after 50 cycles and with efficiencies over 95%. Moreover, cyclic voltammetry (CV) measurements at different rates allowed for a better understanding of the electrochemical behaviour and revealed the contribution relation of diffusive and capacitive-controlled mechanisms in the corresponding AIB system. Further cyclic voltammetry (CV) measurements at different rates allowed a kinetic study of the diffusive and capacitive-controlled mechanisms. The results were interpreted concerning the influence of dimensionality (1D and 2D) of the MnO₂ phases obtained.

Audience take-away:

• New battery technologies
• Learn about rechargeable aluminium batteries
• Understand the importance of the chemical and physical structure of materials in their electrochemical behaviour.

Biography:

I have developed my research career in the field of materials science, evolving from the most basic science in the initial stage to their final applications in different fields, highlighting energy storage devices. I obtained my PhD in physics at the Complutense University of Madrid in 2019. During my PhD I collaborated with different groups to develop new batteries, such as zinc-air electrodes or composite materials for lithium-ion battery anodes. Since September 2019 I have been working at Albufera Energy Storage, where I have been researching on the development of advanced materials and improved electrolytes for aluminium batteries technology.