In Situ N, O-Dually Doped Nanoporous Biochar Derived from Waste Eutrophic Spirulina for High-Performance Supercapacitors

Yihao Geng; Jieni Wang; Xuanyu Chen; Qizhao Wang; Shuqin Zhang; Yijun Tian; Chenxiao Liu; Lin Wang; Zhangdong Wei; Leichang Cao; Jinglai Zhang; Shicheng Zhang

doi:10.3390/nano13172431

In Situ N, O-Dually Doped Nanoporous Biochar Derived from Waste Eutrophic Spirulina for High-Performance Supercapacitors

Nanomaterials (Basel). 2023 Aug 27;13(17):2431. doi: 10.3390/nano13172431.

Authors

Yihao Geng¹, Jieni Wang^{1

2}, Xuanyu Chen¹, Qizhao Wang¹, Shuqin Zhang^{1

2}, Yijun Tian^{1

2}, Chenxiao Liu^{1

2}, Lin Wang¹, Zhangdong Wei¹, Leichang Cao^{1

2}, Jinglai Zhang², Shicheng Zhang³

Affiliations

¹ Miami College, Henan University, Kaifeng 475004, China.
² College of Chemistry and Molecular Sciences, Henan University, Kaifeng 475004, China.
³ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.

Abstract

Sustainable and high-performance energy storage materials are crucial to address global energy and environmental challenges. In this study, Spirulina platensis was used as the carbon and nitrogen source, and Spirulina-based nanoporous biochar (SNPB) was synthesized through chemical activation using KOH as the activating agent in N₂ atmosphere. SNPB-800-4 was characterized by N₂ adsorption-desorption and XPS, showing a high specific surface area (2923.7 m² g^-1) and abundant heteroatomic oxygen (13.78%) and nitrogen (2.55%). SNPB-800-4 demonstrated an exceptional capacitance of 348 F g^-1 at a current density of 1 A g^-1 and a remarkable capacitance retention of 94.14% after 10,000 cycles at a current density of 10 A g^-1 in 6 M KOH. Notably, symmetric supercapacitors SNPB-800-4//SNPB-800-4 achieved the maximum energy and power densities of 17.99 Wh kg^-1 and 162.48 W kg^-1, respectively, at a current density of 0.5 A g^-1, and still maintained 2.66 Wh kg^-1 when the power density was increased to 9685.08 W kg^-1 at a current density of 30 A g^-1. This work provides an easily scalable and straightforward way to convert waste algae biomass into in situ N, O-dually doped biochar for ultra-high-power supercapacitors.

Keywords: algae biomass; energy storage; nanoporous biochar; supercapacitor.

Grants and funding

The authors are thankful for the financial support from the National Natural Science Foundation of China (No. 52100164), the China Postdoctoral Science Foundation (No. 2023M731169), the Key Scientific Research Projects of Universities in Henan Province (No. 23A610006), the Key Science and Technology Department Project of Henan Province (No. 222102320252), the Science and Technology Development Plan of Kaifeng City—Science and Technology Research Project, and Yellow River Scholar Program of Henan University.