Designing spacial skeleton for lithium metal anode with Li+ concentration regulation and interfacial modification

Highlights: • The ideally uniform MgO modification via ALD can regulate the Li nucleation. • The Li⁺ storage in micropores can regulate Li⁺ concentration and avoid Li⁺ depletion. • The controllable delithiation potential of HPGC can prevent dead-Li formation. -- Abstract: Lithium metal has been considered as one of the most promising anodes for the endeavoring pursuit of advanced batteries due to its ultra-high capacity of ~3860 mAh g⁻¹. To solve the current problems of lithium metal anode (LMA), such as unrollable dendritic growth, dead Li accumulation, and the resulted pulverization, three-dimensional frameworks have been adopted to maintain the structural integrity of LMA, but the issues including interfacial stability and affinity, undesired Li-ion deletion at the electrolyte/electrode interface are still challenging. Herein, by adopting hierarchical porous graphitic carbon (HPGC) as LMA skeleton and the atomic-level MgO for interface modification, the ideally uniform interface with strong Li affinity can effectively regulate the nucleation and deposition behavior of Li metal; while with the large quantity of Li⁺ storage in the micro-porous of HPGC, both the spatial confinement of Li⁺ flux and the increase in Li⁺ concentration at electrode/electrolyte interface can be achieved to facilitate the planer Li metal electrodeposition. Furthermore, the delithiation of HPGC with slightly higher potential can effectively reduce the formation of dead-Li via preventing the depletion of Li with inexhaustible Li⁺ storage during stripping process. The superiority of MgO@HPGC hosted LMA can be demonstrated both as coating layer and interior skeleton for different kinds of LMA applications, with enhancement in both long term cycling stability (~650 h) and high coulombic efficiency (~97%) over 390 cycles.