Nanofiber-interlocked holey graphene composite aerogel with self-adapting mechanical resilience for a highly reversible dendrite-free lithium metal anode

Lithium (Li) metal, with the highest theoretical capacity, is considered the most promising anode in lithium metal batteries (LMBs) despite the undesirable growth of Li dendrites and large volume change during long-term cycling. Although three-dimensional (3D) hosts such as graphene aerogels are usually used to accommodate the Li metal, pure graphene aerogels can barely withstand large volume changes during the charge/discharge process. Herein, a polyimide (PI) nanofiber-interlocked holey graphene (HG) composite aerogel (CA) with self-adapting mechanical resilience, denoted as PI-HGCA, is prepared as a hierarchically porous host to accommodate Li metal. The HG nanosheets with in-plane nanopores can effectively regulate Li-ion flux and provide highly directed ion transfer pathways. Furthermore, the 3D CA host, constructed with horizontally aligned HG layers and interlocked PI nanofibers, exhibits highly reversible self-adapting compression resilience to large volume change during long-term cycling. Consequently, the lithiated PI-HGCA anode shows a relatively low overpotential of 46 mV with a long lifespan of 1300 cycles in the symmetrical cell and displays an ultrahigh capacity retention of 81.2% after 800 cycles at 1 C coupled with a LiFePO 4 cathode, demonstrating the great potential of the interlocked aerogels in high-energy-density LMBs.