Site-specific self-protection of stacking faults enables durable Li-gas batteries.

Rechargeable Li-gas batteries, represented by Li-O2 and Li-CO2 systems, are promising for high-energy-density storage and gas-involved energy conversion, yet their operation is constrained by the trade-off between catalytic activity and structural durability of cathodes. Metastable defects such as stacking faults offer active sites for accelerating sluggish gas redox reactions, but readily undergo electrochemical stress-induced slip and structural collapse during cycling. Inspired by plant traumatic resinosis, we propose a site-specific self-protection strategy that exploits the intrinsic anisotropy of stacking faults to decouple catalytic reaction planes from orthogonal protective functional planes. On the reaction plane, over-coordinated dislocation sites amplify surface electrostatic potential differences and promote Li2CO3 decomposition via nucleophilic/electrophilic interactions. On the functional plane, selective interactions with sulfur-containing electrolyte components induce in situ reconstruction of a multiphase inorganic-organic amorphous interphase, anchoring stacking faults without blocking catalytic sites. As a Li-CO2 proof of concept, stacking-fault-rich molybdenum boride (MoB) delivers 90.13% average energy efficiency over 2500 h and stable operation at 150 °C for nearly 500 h. This work establishes a self-protection paradigm for stable metastable active structures and provides a universal interface design principle for durable Li-gas batteries.