PNNL

Abstract

Solving the lithium (Li) metal problem is one of the most significant challenges for future high energy batteries. Despite significant efforts to stabilize Li-metal anode structures and prevent dendrite formation, achieving long cycling life in high energy cells remains extremely difficult due to a combination of complex failure modes involving accelerated anode degradation, and depletion of the electrolyte and the Li metal. Here, we report a stable and self-smoothing Li anode structure based on amine-functionalized three-dimensional (3D) carbon fibers for long-cycling life full cells under conditions required for high energy, rechargeable Li-metal batteries. Reversible and smooth Li deposition and stripping is realized on the new anode structure, in contrast with the porous and dendritic Li layers that develop on a pure Li-metal surface. The stable, self-smoothing anode coupled with high-capacity LiNi0.8Mn0.1Co0.1O2 delivers stable cycling using parameters for a high energy cell with a specific energy of more than 380 Wh kg-1, counting all active and inactive components in a single cell, in particular with a high cathode loading, thin Li metal and lean electrolyte. The cycling life of the cell is increased by more than an order of magnitude compared to the cell using a flat Li-metal anode.