Localized Ligands Assist Ultrafast Multivalent-Cation Intercalation Pseudocapacitance.

Rechargeable batteries based on multivalent cation (Mv n+ , n>1) carriers are considered potentially low-cost alternatives to lithium-ion batteries. However, the high charge-density Mv n+ carriers generally lead to sluggish kinetics and poor structural stability in cathode materials. Herein, we report an Mv n+ storage via intercalation pseudocapacitance mechanism in a 2D bivalve-like organic framework featured with localized ligands. By switching from conventional intercalation to localized ligand-assisted-intercalation pseudocapacitance, the organic cathode exhibits unprecedented fast kinetics with little structural change upon intercalation. It thus enables an excellent power density of 57 kW kg -1 over 20000 cycles for Ca 2+ storage and a power density of 14 kW kg -1 with a long cycling life over 45000 cycles for Zn 2+ storage. This work may provide a largely unexploited route toward constructing a local dynamic coordination microstructure for ultrafast Mv n+ storage.