Ni–Co layered double hydroxides (LDHs) have high theoretical capacities for energy storage by ion intercalation/
release but suffer from the sluggish charge transport kinetics, hence are unsuitable for high-power supercapacitors
nowadays. Herein, by intercalating the guest multi-carboxylic anions with straight-chain or
conjugated-plane configurations, we have realized the sub-nanometer-scale fine regulation of the interlayer
distance in Ni–Co LDHs for tuning the charge (ions and electrons) transport kinetics. With increasing the
interlayer distance, the equivalent series resistance (RESR) shows the "inverted-volcano" evolution, which is first
demonstrated for the anion-intercalated LDHs. With the smallest RESR, the LDH pillared by the conjugated 1,4-
benzenedicarboxylic anion achieves the best matching between ion diffusion and electron transfer, and thus
presents a high capacitance of 2115 F g 1 at 1 A g 1 and a record-high rate capability for the powder-like LDHs
with the capacitance of 410 F g 1 at an ultrahigh current density of 150 A g 1. The corresponding hybrid
supercapacitor coupled with activated carbon presents the high energy density of 11.2 Wh kg 1 at the ultrahigh
power density of 30.7 kW kg 1, ranking at the top level for the supercapacitors based on the powder-like LDHs
active materials. The minimal RESR from the "inverted-volcano" evolution could provide a feasible criterion to
explore the high-rate LDH electrodes.
Jie Zhao,Chengxuan Ge,Zhiyang Zhao,Qiang Wu,Meng Liu,Minglei Yan,Lijun Yang,Xizhang Wang,Zheng Hu.