An ultralight porous carbon scaffold for anode-free lithium metal batteries†

Abstract

Anode-free lithium metal batteries (ALMBs) are promising due to their high energy density, cost-effectiveness, and simple design. However, they face significant challenges, including slow electrode kinetics, dendrite formation leading to safety concerns, and volume expansion that results in an unstable solid electrolyte interface (SEI). To overcome these obstacles, based on our results we propose replacing the conventional copper foil (Cu-foil) with porous carbon nanomaterials that function as both a lithium host and current collector. A thin sheet of carbon grapes (TSCG) has been specifically synthesized to provide a continuous surface for lithium plating and stripping while storing dead lithium in its voids and pores. The TSCG-based ALMBs exhibit extremely fast charging rates (∼5–10 mA cm⁻²), reduced volume expansion and a stable SEI, and effective dendrite suppression by trapping dead mossy lithium. In full cells, where lithium iron phosphate (LFP) is used as the cathode, TSCG achieves a Coulombic efficiency of approximately 98% (specific capacity ∼250 mA h g⁻¹), which improves to about 99% with pre-lithiation (specific capacity ∼300 mA h g⁻¹). This technology is also applied to all-solid-state batteries, enhancing safety with solid-state electrolytes. This research paves the way for developing high-performance, anode-free ALMBs using carbon nanostructures.