Multi-metal anode: Towards safe and energy dense batteries

Introduction

Li metal is considered to be the holy grail anode material due to its high specific capacity and low standard redox potential. It could, in theory, lead to the assembly of extremely high energy density cells.

Background

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. This potential has motivated important research efforts in:

1. Li-air
2. Li-Sulfur
3. Solid state batteries (SSB)

Challenges

Unfortunately, all of these technologies (even SSB) suffer from dendritic Li growth, which eventually results in short circuit or thermal runaway.

Requirements for Smooth Li Metal Electrodeposition

Requirements for smooth Li metal electrodeposition mostly consist of:

• Fine control of the cation mass transport through the solid electrolyte interphase (SEI)
• Composition, morphology, and stability of the SEI

Despite several decades of investigation, it is virtually impossible to achieve the perfect interphase/interface that can sustain thousands of cycles under real battery operation conditions.

Objectives of MULTIMETALBAT

The main objective of MULTIMETALBAT is to bring a new paradigm for metal anodes by developing electrolytes containing a mixture of multiple cations (Li+, Na+, K+, Ca2+, or Mg2+). This approach will modify the overall thermodynamics of plating and stripping compared to conventional single metal anodes.

Key Strategies

• Promote kinetic competition between various electrodeposition processes
• Engineer the SEI to sustain high mechanical, chemical, and thermal stability
• Help promote homogeneous cation diffusion through the SEI

Targeted Figures of Merit

Targeted figures of merit include:

i) Critical current density for 3D metal growth above 10 mA.cm^-2
ii) 350 Wh/kg energy density for 100 mAh pouch cells, almost doubling that of current Li-ion batteries.

Safety Considerations

Yet, the main objective of MULTIMETALBAT will be increased safety. Extensive standard safety measurements will be performed on prototype cells and compared with Li-ion batteries.