Nitrogen-Doping-Driven 3D Interwoven Nickel–Cobalt Layered Double Hydroxides on Wood Tracheid Inner Walls for Ultrahigh Areal Capacitance Supercapacitors
Lixin Wang, Ran Wang, Jie Ouyang, Zhexuan Liu, Yi Tian, Mengting Cheng, Yuzhu Wang, Wei Yin, Yijiao Geng, Zhuoshi Wu, Jianhua Luo, Jinpeng Cai, Yongfeng Luo
Abstract
A two-step electrochemical deposition strategy is proposed to construct a ternary heterostructure of nickel–cobalt layered double hydroxides (NiCo-LDH) on nitrogen-doped MnO 2 -coated nitrogen-doped wood carbon (NDC). The nitrogen doping induces a morphological evolution of NiCo-LDH from 2D nanosheets to a 3D interwoven architecture on wood tracheid inner walls, significantly enhancing the specific surface area and ion diffusion kinetics. Benefiting from the synergistic effects between the 3D NiCo-LDH network, conductive MnO 2, and hierarchical porous NDC substrate, the composite electrode achieves an exceptional areal capacitance of 21.56 F cm –2 at 10 mA cm –2 with 80.9% retention at 40 mA cm –2 . The assembled asymmetric supercapacitor delivers a high energy density of 0.52 mWh cm –2 and a power density of 5.79 mW cm –2, alongside outstanding cycling stability (94.24% retention after 8,000 cycles). This work provides an approach for designing biomass-derived carbon-based electrodes with 3D structural engineering, demonstrating significant potential for advanced energy storage applications.