Multi-metal anode: Towards safe and energy dense batteries

ongoing

Li metal is considered to be the holy grail anode material due to its high specific capacity and low standard redox potential and could, in theory, lead to the assembly of extremely high energy density cells. Metal anode based batteries, in general, represent the main viable option towards a leapfrog in terms of energy density when compared with current Li-ion technology, thus motivating important research efforts in Li-air, Li-Sulfur and, more recently, solid state batteries (SSB). Unfortunately, all of these technologies (even SSB) suffer from dendritic Li growth, eventually resulting in short circuit/thermal runaway. Requirements for smooth Li metal electrodeposition, mostly consist in the fine control of the cation mass transport through the solid electrolyte interphase (SEI), which in turn is governed by the composition, morphology and stability of the latter. Unfortunately, and after several decades of investigation, it is virtually impossible to achieve the perfect interphase/interface which can sustain thousands of cycles in real battery operation conditions. The main objective of MULTIMETALBAT is to bring a new paradigm for metal anode by developing electrolytes containing a mixture of multiple cations (Li+, Na+, K+, Ca2+ or Mg2+) which will modify the overall thermodynamics of plating and stripping when compared with conventional single metal anode. Kinetic competition between various electrodeposition processes will be promoted and the SEI will be engineered to sustain high mechanical, chemical and thermal stability, hence helping promoting homogeneous cation diffusion through it. Targeted figures of merit include: i) critical current density for 3D metal growth above 10 mA.cm-2 and ii) 350 Wh/kg energy density for 100 mAh pouch cells, almost doubling that of current Li-ion. Yet, the main objective of MULTIMETALBAT will be increased safety and extensive standard safety measurements will be performed on prototype cells and compared with Li-ion batteries.