Pre-Lithiation Strategies for Rechargeable Energy Storage Technologies: Concepts, Promises and Challenges

In order to meet the sophisticated demands for large-scale applications such as electro-mobility, next generation energy storage technologies require advanced electrode active materials with enhanced gravimetric and volumetric capacities to achieve increased gravimetric energy and volumetric energy densities. However, most of these materials suffer from high 1st cycle active lithium losses, e.g., caused by solid electrolyte interphase (SEI) formation, which in turn hinder their broad commercial use so far. In general, the loss of active lithium permanently decreases the available energy by the consumption of lithium from the positive electrode material. Pre-lithiation is considered as a highly appealing technique to compensate for active lithium losses and, therefore, to increase the practical energy density. Various pre-lithiation techniques have been evaluated so far, including electrochemical and chemical pre-lithiation, pre-lithiation with the help of additives or the pre-lithiation by direct contact to lithium metal. In this review article, we will give a comprehensive overview about the various concepts for pre lithiation and controversially discuss their advantages and challenges. Furthermore, we will critically discuss possible effects on the cell performance and stability and assess the techniques with regard to their possible commercial exploration.