α-Fe2O3 anchored on porous N doped carbon derived from green microalgae via spray pyrolysis as anode materials for lithium ion batteries

Using algae in Li-ion batteries: A sustainable pathway toward greener energy storage

This paper reviews and analyzes the innovations and advances in using algae and their derivatives in different parts of Li-ion batteries. Applications in Li-ion battery anodes, electrolytes, binders, and separators were discussed. Algae provides a sustainable feedstock for different materials that can be used in Li-ion batteries, such as carbonaceous material, biosilica, biopolymers, and other materials that have unique micro- and nano-structures that act as biotemplates for composites structure design. Natural materials and biotemplates provided by algae have various advantages, such as electrochemical and thermal stability, porosity that allows higher storage capacity, nontoxicity, and other properties discussed in the paper. Results reveal that despite algae and its derivatives being a promising renewable feedstock for different applications in Li-ion batteries, more research is yet to be performed to evaluate its feasibility of being used in the industry.

One-dimensional N-doped carbon nanofibers produced by pre-oxide treatment for effective lithium storage

Amorphous carbon materials have been confirmed as attractive anode materials for lithium-ion batteries. Herein, an effective strategy to fabricate amorphous carbon materials at low temperature under air atmosphere is proposed. As demonstrated, one-dimensional nitrogen-doping carbon nanofibers were obtained through simple electrospinning technology, following low-temperature heat treatment. Meanwhile, the nitrogen-doping concentration can be regulated by the heating temperature, which can further introduce different levels of adsorption sites on the surface of carbon and enhance the electronic conductivity. Based on experimental investigation, carbon nanofibers with a high nitrogen doping concentration of 18.1 at% achieved an outstanding cycling durability (194.0 mA h g^-1 at 2.0 A g^-1 after 2000 cycles).

Confinement of MnOx@Fe2O3 core-shell catalyst with titania nanotubes: Enhanced N2 selectivity and SO2 tolerance in NH3- SCR process

Surface interface regulation is an important research content in the field of heterogeneous catalysis. To improve the interface interaction between the active component and matrix, tremendous efforts have been dedicated to tailoring the morphology, size, and structure of composite catalysts. In this work, we report a confinement strategy to synthesize a series of core-shell catalysts loaded with metal oxides on titania nanotubes (TNTs), which were applied to the selective catalytic reduction of NO_x with ammonia. Interestingly, the core-shell catalyst with confinement of TNTs exhibited the remarkable activity at low temperature region, N₂ selectivity and sulfur tolerance. Benefiting from the superior interfacial confinement characteristic of TNTs and Fe₂O₃, strong component interactions, the surface acid sites and strong oxidizability of MnO_x were properly regulated, thus obtained the outstanding activity, N₂ selectivity and provide chemical protection to effectively prevent SO₂ poisoning. As far as the reaction mechanism, we found that the adsorption and reactivity of Lewis acid sites were the dominant factors affecting the activity in the NH₃-SCR process by in situ DRIFT spectra. In general, our work provides an innovative strategy for constructing an TNTs-enwrapped nanocomposite with nano-confinement and core-shell structure to improve the low temperature SCR process.

An abundant porous biochar material derived from wakame (Undaria pinnatifida) with high adsorption performance for three organic dyes

In this study, an activated wakame biochar material (AWBM) was prepared by a one-step calcination and activation method, whose adsorption performances for methylene blue (MB), Rhodamine B (RB) and malachite green (MG) were also analyzed. The results showed AWBM was a mesoporous fluffy structure material with a higher specific surface (1156.25 m2/g), exhibiting superior adsorption capacities for MB (841.64 mg/g), RB (533.77 mg/g) and MG (4066.96 mg/g), respectively. In addition, FT-IR analysis showed that AWBM possessed abundant active groups (such as -OH, -CO and -CH), further enhancing the adsorption efficiencies. The Langmuir model could better fit the three dyes adsorption isotherms process using AWBM, and the Pseudo-second-order model could better describe the adsorption kinetic experimental data. The thermodynamic analysis showed that the three dyes adsorption using AWBM was spontaneous endothermic reaction. This study suggests AWBM has enormous potential in the application of removing organic dyes from wastewater.

Propelling electrochemical kinetics of transition metal oxide for high-rate lithium-ion battery through in situ deoxidation

To engineer advanced anodes for high-rate lithium-ion battery, rational structural design with insightful understanding of rapid reaction kinetics is important and still highly desirable. In this work, a high-temperature in situ deoxidation strategy is used to propel electrochemical kinetics of NiO through incorporating an intrinsic Ni component. Both theoretical calculation and experimental study demonstrate that the Ni-NiO heterojunction significantly enhances the electronic conductivity and ion diffusion properties. Accordingly, the lithium-ion battery modified with the heterostructured Ni-NiO shows remarkably improved charge transfer efficiency and rate performance, substantially outperforming many reported NiO-based anodes. This work opens up the exploration of heterostructured metal compounds as kinetic regulators for high-rate lithium-ion battery and also enlightens the understanding of defect chemistry in propelling electrochemical reactions.

Magnetic field assisted high capacity durable Li-ion battery using magnetic α-Fe2O3 nanoparticles decorated expired drug derived N-doped carbon anode

We have synthesized a novel ferromagnetic material by coating α-Fe₂O₃ nanoparticles with N-doped carbon matrix using a simple combustion method. Expired paracetamol drugs are used as nitrogen and carbon source. This α-Fe₂O₃/NC shows ferromagnetic property due to the incorporation of oxygen defects. When used as the Li-ion battery anode, α-Fe₂O₃/NC shows higher capacity compared to commercial α-Fe₂O₃ due to the occurrence of both intercalation and conversion reaction. Further, application of magnetic field at the anode of the freshly assembled cell at the first charge-discharge cycle, results in ~two-fold enhancement in specific capacity. For the cycled cell also, increase in the capacity from 80 mAh. g^-1 to 150 mAh. g^-1 at 5 A. g^-1 is observed during the application of magnetic field at the 501^st charging cycle. This improved performance is attributed to the field-dependent enhancement of diffusion and convection due to the magnetohydrodynamic effect. Further, application of the magnetic field at 1001^st, 1501^st and 1751^st charging cycles shows improved LIB performance. We can show that not only the magnetic field, magnetic properties of the anode α-Fe₂O₃/NC also play a crucial role in influencing the battery performance. Moreover, utilization of expired drug helps in dramatically reducing pollution caused by its disposal.

The lithium ions storage behavior of heteroatom-mediated echinus-like porous carbon spheres: From co-doping to multi-atom doping

This study proposed a facile method to prepare echinus-like porous carbon spheres (PCS) with different heteroatom doping for lithium ions battery (LIBs). A metal-organophosphine framework (MOPF) was synthesized by employing riboflavin sodium phosphate as an organic ligand to conjugate with metal ions and then carbonized at mild temperature, leading to the formation of heteroatom doped PCS (H-PCS). As a result, (N, P) co-, (N, P, Ni) tri-, (N, P, Co) tri- and (N, Ni, Co, P) tetra-doped PCS were obtained to examine the insight into lithium-ion storage behavior of H-PCS. It was found that the specific surface area, pore texture and structural defects of H-PCS were dependent on doping of heteroatoms as well as the charge transfer resistance and Li-ion diffusion coefficient. Significantly, the redox reaction potential during the charge/discharge could be mediated upon the doping. Thus, when evaluated as anode for LIBs, the (N, Ni, Co, P) tetra-doped PCS exhibited highly reversible capacity of 680 mAh g^-1 at 0.1 A g^-1, excellent rate capability (115.9 mAh g^-1 at 1.0 A g^-1) and superior cycling performance (399.6 mAh g^-1 at 0.1 A g^-1). Moreover, the cyclic voltammogram measurements demonstrated that the doping of metal atoms was favorable for improving the capacitive contribution of surface limited diffusion. Thus, this work highlighted the importance of HCP with defined doping which could be considered as one of the prominent candidates for high-performance LIBs' anode.