Self‐Confinement Effect Enabled by Hollow Carbon Nanoreactor for High‐Performance Li–Cl ₂ Battery

Rechargeable Li─Cl₂ batteries represent a promising high-energy-density technology. However, the open-pore structure of conventional cathode materials poses a fundamental challenge by permitting the uncontrolled diffusion of Cl₂ into the electrolyte, resulting in severe local concentration dilution that plagues rate capability and specific capacity. Herein, a self-confinement strategy by hollow carbon nanoreactors (HCNRs) is proposed to regulate the local concentration of active Cl₂ species with micropores (≈0.8 nm) on their walls. These micropores act as size-selective barriers, allowing to block the escape of larger active Cl₂ species (kinetic diameter ≈0.86 nm), and mesopores (30-50 nm) function as nanoreactors that concentrate active Cl₂ species. This design enables the as-assembled Li─Cl₂ cell to achieve an ultrahigh current density of 100 mA cm^-2 during the charge/discharge process and a record-breaking specific capacity of 8000 mAh g^-1 (9 mAh cm^-2), superior to the reported literature. This hollow nanoreactor design highlights the potential of Li─Cl₂ batteries as high-power and energy-dense systems, paving the way for their practical application.