Reversible dendrite-free Li-plating/stripping electrochemistry achieved by stress-regulating carbon aerogel

ABSTRACT The stress distribution in Li metal strongly affects the interfacial Li-ion diffusion, thereby influencing the morphology of plated Li and the performance of the battery. Here, we report a mechano-electrochemical coupling strategy that utilizes an arched structured carbon aerogel to achieve stable Li-plating/stripping electrochemistry. The arch-structured carbon aerogel can actively regulate stress distributions in response to the compressive stresses induced by Li deposition, generating the transition of stress from compressive on the convex surface to tensile on the concave surface, which can effectively promote the Li-migration kinetics and thus suppress the non-uniform deposition of Li. The carbon aerogel with synergistically enriched-oxygen vacancies on its surface boosts rapid interfacial Li-ion migration by reducing the Li+ migration barrier. The non-dendritic Li-metal anode demonstrates smaller electrode level volume variation (<3%), higher coulombic efficiency (98.5%) and a longer cycle lifetime (2000 h at 1 mA cm−2) than conventional planar substrates. A full cell based on the LiFePO4 cathode shows a high capacity retention of 90.2% after 300 cycles at 1 C. The carbon-aerogel/Li|sulfurized polyacrylonitrile full cell delivers a reversible capacity of 1130 mA h g−1 over 270 cycles at 0.2 C. This work reveals a stress-driven dendrite growth suppression mechanism and provides insights into the design of dendrite-free metal anodes for rechargeable metal batteries.