Role of Two-Dimensional Nanomaterials in Electrodes for Rechargeable Batteries and Supercapacitors

Introduction

The use of electricity produced by renewable energies like wind, solar, and water-power has become necessary due to the energy crisis and environmental damage (Tang, 2018). However, because these renewable energies are sporadic, it is crucial to create energy storage technologies for their better exploitation. It has become imperative to create rechargeable batteries and supercapacitors with improved electrochemical performance, especially since conventional energy storage technologies are unable to satisfy the energy market's present and future expectations (Zhang, 2022). Advanced electrode materials with superior electrochemical performance, high-energy density, and high-power density are being developed with great effort for energy storage. Two-dimensional materials have mainly become in the last decade ideal candidates for energy applications due to their outstanding electrical, chemical, and physical properties (Fan, 2021). Among the advantages that these materials can offer are a high surface-volume surface rate, good transport properties, excellent physicochemical properties, and remarkable confinement effects. Additionally, the morphology of these materials allows controllable interfacial chemistry, high electrical conductivity, tunable layers structure, high porosity, modifiable by functional groups, controllable chemical composition, small strain expansion, etc. (Mao, 2021; Rasheed, 2022). Due to these characteristics, two-dimensional materials are being applied in energy storage, electrocatalysis, medicine, water purification, superconductivity, etc. (Guo, 2020). However, its practical applicability in energy storage systems is limited due to the low efficiency of material use, slow reaction kinetics, and limited active sites. To overcome these restatements, it is necessary to improve the electrochemical performance of these materials through rational microstructural design and synthesis. A synergistic effect between materials has been found when using 0D-2D composites, 1D-2D composites, 2D-2D composites, nanosheet-substrate composites, and core-shell composites (Oh, 2020).

In comparison to ordinary capacitors, which have a very high capacitance of up to 10,000 F, supercapacitors have a high-energy density and high-power density (Dongre, 2022). Supercapacitors (SCs) have received a lot of interest recently in energy storage, and research efforts are heavily reliant on the design and engineering of efficient electrode materials (Qin, 2020). Rechargeable batteries that use an aqueous electrolyte are categorized as Li⁺-, Na⁺-, K⁺-, Zn²⁺-, Ca²⁺-, Mg²⁺-, Al³⁺-, or Cl^--ion aqueous batteries depending on the kind of principal charge carrier (Choi, 2021). The development of advanced batteries has also been stimulated by the desire for greater efficiency and lower emissions following decades of the energy revolution. These batteries frequently have the advantages of improved cycling stability, high specific capacity, high energy density, and long service lives (Zhang, 2022). The anode must be both ionically and electrically conductive for a battery to operate at high rates.

Graphene, a two-dimensional carbon nanosheet, has remained the main source of scientific fascination for energy storage in the last decade (Kumar, 2018). Among the two-dimensional materials of the IV-A group used as electrodes are graphene (C), silicene (Si), germanene (Ge), stanene (Sn), and plumbene (Pb) (Guo, 2020). In the V-A group, two-dimensional materials that have been used as an electrode in energy storage devices are phosphorene or black-phosphorus (P) (Zhu, J.P. 2020), arsenene (As) (Benzidi, 2019), antimonene (Sb) (Liang, 2021), and bismuthene (Bi) (Zhou, 2019). In addition, there are compound two-dimensional materials such as metal-organic frameworks (MOFs) (Zhang, 2022), transition metal nitrides and carbides (MXenes) (Rasheed, 2022), transition metal dichalcogenides (TMDs) (Peng, 2016), and 2D metal oxides (Mendoza-Sánchez, 2016). There is another group of emerging two-dimensional materials that are also being used in energy storage devices such as electrodes such as InSe (Sun, 2019), metal thiophosphates (Zhu, M. 2020), spinel ferrites (Mao, 2021), perovskite oxides (Qin, 2020), and transition metals sulfides (Maksoud, 2021), etc.