Regulating the nucleation and growth of Li metal is crucial for achieving stable high-energy-density Li metal batteries (LMBs) without dendritic Li growth, severe volume expansion, and "dead Li" accumulation. Herein, we present a modulation layer composed of porous SnP_0.94/CoP p-n heterojunction particles (SCP), synthesized applying the Kirkendall effect. The unique heterointerfaces in the SCP induce a fully ionized depletion region and built-in electric field. This provides strong Li affinity, additional adsorption sites, and facilitated electron transfer, thereby guiding dendrite-free Li nucleation/growth with a low Li deposition overpotential. Moreover, the strategic design of the SCP, accounting for its reaction with Li, yields electronically conductive Co, lithiophilic Li-Sn alloy, and ionic conductive Li₃P during progressive cycles. The mixed electronic and ionic conductor (MEIC) ensure the long-term stability of the SCP modulation layer. With this layer, the SCP@Li symmetric cell maintains a low overpotential for 750 cycles even at a high current density of 5 mA cm^-2. Additionally, the LiFePO₄//SCP@Li full cell achieves an imperceptible capacity decay of 0.03% per cycle for 800 cycles at 0.5 C. This study provides insight into MEIC heterostructures for high-performance LMBs.

Doped two-dimensional (2D) materials hold significant promise for advancing many technologies, such as microelectronics, optoelectronics, and energy storage. Herein, n-type 2D oxidized Si nanosheets, namely n-type siloxene (n-SX), are employed as Li-ion battery anodes. Via thermal evaporation of sodium hypophosphite at 275 °C, P atoms are effectively incorporated into siloxene (SX) without compromising its 2D layered morphology and unique Kautsky-type crystal structure. Further, selective nucleophilic substitution occurs, with only Si atoms being replaced by P atoms in the O₃≡Si-H tetrahedra. The resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types: (i) P atoms residing in Si sites and (ii) H vacancies. The doping concentrations are varied by controlling the amount of precursors or their mean free paths. Even at 2000 mA g^-1, the n-SX electrode with the optimized doping concentration (6.7 × 10¹⁹ atoms cm^-3) delivers a capacity of 594 mAh g^-1 with a 73% capacity retention after 500 cycles. These improvements originate from the enhanced kinetics of charge transport processes, including electronic conduction, charge transfer, and solid-state diffusion. The approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.