Biocompatible Mesoporous Hollow Carbon Nanocapsules for High Performance Supercapacitors

Lijian Wang,Yuesheng Ning,Binyuan Zhao,Chengbin Yang,Ken-Tye Yong,Weiping Wu,Robert Bradley,Fenghua Liu

doi:10.1038/s41598-020-61138-4

Abstract

A facile and general method for the controllable synthesis of N-doped hollow mesoporous carbon nanocapsules (NHCNCs) with four different geometries has been developed. The spheres (NHCNC-1), low-concaves (NHCNC-2), semi-concaves (NHCNC-3) and wrinkles (NHCNC-4) shaped samples were prepared and systematically investigated to understand the structural effects of hollow particles on their supercapacitor performances. Compared with the other three different shaped samples (NHCNC-1, NHCNC-2, and NHCNC-4), the as-synthesized semi-concave structured NHCNC-3 demonstrated excellent performance with high gravimetric capacitance of 326 F g−1 (419 F cm−3) and ultra-stable cycling stability (96.6% after 5000 cycles). The outstanding performances achieved are attributed to the unique semi-concave structure, high specific surface area (1400 m2 g−1), hierarchical porosity, high packing density (1.41 g cm−3) and high nitrogen (N) content (up to 3.73%) of the new materials. These carbon nanocapsules with tailorable structures and properties enable them as outstanding carriers and platforms for various emerging applications, such as nanoscale chemical reactors, catalysis, batteries, solar energy harvest, gas storage and so on. In addition, these novel carbons have negligible cytotoxicity and high biocompatibility for human cells, promising a wide range of bio applications, such as biomaterials, drug delivery, biomedicine, biotherapy and bioelectronic devices.

Highlights

Supercapacitors have drawn increasing attention due to their high power density, fast charge/discharge capability, long cycle life, low cost and environmental friendliness among various electrochemical energy storage devices[1]
We present a facile, controllable one-step method of synthesizing N-doped hollow porous carbon nanocapsules (NHCNCs) with four different morphologies in a single synthetic system
The electrochemical impedance spectroscopy (EIS) of N-doped hollow mesoporous carbon nanocapsules (NHCNCs) was measured from 10−1 Hz to 105 Hz (Fig. 6a)

Summary

Introduction

Supercapacitors have drawn increasing attention due to their high power density, fast charge/discharge capability, long cycle life, low cost and environmental friendliness among various electrochemical energy storage devices[1]. Compared with the other three shapes (NHCNC-1, NHCNC-2, and NHCNC-4), the as-synthesized NHCNC-3 with semi-concave structure has an excellent balance between pore volume and compact density, resulting in excellent electrochemical performances This new nanoscale material architecture combines several advantages and benefits for electrode applications: (1) better connection with neighboring particles and thinner shell with mesoporous structures, resulting into reduced ion-transport resistance which enables ion transport at high electrical current density; (2) hierarchical porous structures; (3) lower void volume showing increased mass density due to their better stacking behaviour which will greatly contribute to volumetric capacitance; (4) relatively high content of nitrogen heteroatoms could provide a certain amount of pseudocapacitance. This work provides a good example on the correlation between carbon nanocapsule structures and their electrochemical performances

Methods

Results

Conclusion