Heteroatom tuning in agarose derived carbon aerogel for enhanced potassium ion multiple energy storage

The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains unclear.In this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom doping.Electronic states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N atoms.As a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O doping.As K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate performance.Especially,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.

Environmental life cycle assessment of supercapacitor electrode production using algae derived biochar aerogel

Porous carbon aerogel material has gained an increasing attraction for developing supercapacitor electrodes due to its cost-effective synthesis process and relatively high electrochemical performance.However,the environmental performances of supercapacitor electrodes produced from different carbon aerogel materials are never comparatively studied,hindering our knowledge of supercapacitor electrode production in a sustainable pattern.In this study,nitrogen-doped biochar aerogel-based electrode(BA-electrode)produced from Entermorpha prolifera was simulated to investigate the environmental performance by using life cycle assessment method.For comparison,the assessment of graphene oxide aerogel-based electrode(GOA-electrode)was also carried out.It can be observed that the life cycle global warming potential for the BA-electrode was lower than that of GOA-electrode with a reduction of 53.1‒68.1%.In comparison with GOA-electrode,the BA-electrodes endowed smaller impacts on environment in majority of impact categories.Moreover,in comparison with GOA-electrode,the environmental damages of BA-electrode were greatly decreased by 35.8‒56.4%(human health),44.9‒62.6%(ecosystems),and 87.0‒91.2%(resources),respectively.The production stages of GOA and graphene oxide and stages of nitrogen-doped biochar aerogel production and Entermorpha prolifera drying were identified as the hotspots of environmental impact/dam-age for the GOA-electrode and BA-electrode,respectively.Overall,this finding highlights the efficient utilization of algae feedstock to construct a green and sustainable technical route of supercapacitor electrode production.