Sub‐Thick Electrodes with Enhanced Transport Kinetics via In Situ Epitaxial Heterogeneous Interfaces for High Areal‐Capacity Lithium Ion Batteries

Abstract The ever‐growing portable electronics and electric vehicle draws the attention of scaling up of energy storage systems with high areal‐capacity. The concept of thick electrode designs has been used to improve the active mass loading toward achieving high overall energy density. However, the poor rate capabilities of electrode material owing to increasing electrode thickness significantly affect the rapid transportation of ionic and electron diffusion kinetics. Herein, a new concept named “sub‐thick electrodes” is successfully introduced to mitigate the Li‐ion storage performance of electrodes. This is achieved by using commercial nickel foam (NF) to develop a monolithic 3D with rich in situ heterogeneous interfaces anode (Cu 3 P‐Ni 2 P‐NiO, denoted NF‐CNNOP) to reinforce the adhesive force of the active materials on NF as well as contribute additional capacity to the electrode. The as‐prepared NF‐CNNOP electrode displays high reversible and rate areal capacities of 6.81 and 1.50 mAh cm −2 at 0.40 and 6.0 mA cm −2 , respectively. The enhanced Li‐ion storage capability is attributed to the in situ interfacial engineering within the NiO, Ni 2 P, and Cu 3 P and the 3D consecutive electron conductive network. In addition, cyclic voltammetry, charge–discharge curves, and symmetric cell electrochemical impedance spectroscopy consistently reveal improved pseudocapacitance with enhanced transports kinetics in this sub‐thick electrodes.