Self-Confinement Effect Enabled by Hollow Carbon Nanoreactor for High-Performance Li-Cl2 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.