In recent times, solar energy has become one of the largest available sources of renewable energy at our disposal. However, the design of highly efficient solar cells is increasingly becoming crucial as there has been a surge for economically viable alternative energy sources with the lowest cost. Significant advances have been made through different routes to make photovoltaic (PV)/solar technologies economically viable, eco-friendly and consequently scalable. As a result, cellulose nanomaterials have become one of the emerging technologies in this regard because of the advantages of high-value bio-based nanostructured materials, such as their abundance and sustainability. Nanocellulose-based photoactive nanocomposite materials can be made by integrating conducting photoactive and electroconductive materials with hydrophilic biocompatible cellulose. Inorganic nanoparticles, such as graphene/reduced graphene oxide cadmium sulphide quantum dots, amongst others, can be introduced into the nanocellulose matrix and can be applied either as charge transporters or photoactive materials in different types of solar cells. Thus, in this review, we highlight the optoelectronic properties of different photoactive materials, particularly nanocellulose-based graphene nanocomposites; their efficiencies and drawbacks were X-rayed. The effect of doping each PV material on the PV performance is also discussed. It is anticipated that the novel material would result in a reduction in the cost of solar cells, jointly enhancing their efficacy in generating environmentally friendly electricity. Since the fabrication techniques and equipment play a crucial role in the development of solar cells, the fabrication techniques of bulk-heterojunction (BHJ) cells containing a nanocellulose-based graphene composite and case studies of already fabricated BHJ PV cells with nanocellulose-based graphene composite are discussed.

Magnesium–sulfur (Mg-S) batteries represent a novel category of multivalent energy storage systems, characterised by enhanced theoretical energy density, material availability, and ecological compatibility. Notwithstanding these benefits, the practical implementation of this approach continues to be hindered by ongoing issues, such as polysulfide shuttle effects, slow Mg²⁺ transport, and significant interfacial instability. This study emphasises recent progress in utilising transition metal chalcogenides (TMCs) as cathode materials and modifiers to overcome these challenges. We assess the structural, electrical, and catalytic characteristics of TMCs such as MoS₂, CoSe₂, WS₂, and TiS₂, highlighting their contributions to improving redox kinetics, retaining polysulfides, and enabling reversible Mg²⁺ intercalation. The review synthesises results from experimental and theoretical studies to offer a thorough comprehension of structure–function interactions. Particular emphasis is placed on morphological engineering, modulation of electronic conductivity, and techniques for surface functionalisation. Furthermore, we examine insights from density functional theory (DFT) simulations that corroborate the observed enhancements in electrochemical performance and offer predictive direction for material optimisation. This paper delineates nascent opportunities in Artificial Intelligence (AI)-enhanced materials discovery and hybrid system design, proposing future trajectories to realise the potential of TMC-based Mg-S battery systems fully.

The intensifying climate problem requires substantial decarbonisation in the energy, industry, and transportation sectors, with hydrogen recognised as a crucial energy carrier. The increase in global energy consumption, driven by population growth and industrialisation, challenges the constraints of fossil fuel resources and their detrimental impact on CO₂ levels. Hydrogen, noted for its high energy density and versatility in generating power from both fossil and renewable sources, acts as a crucial supplement to direct electrification. Currently, worldwide hydrogen production exceeds 100 million tonnes per year, predominantly in the form of “grey hydrogen,” which significantly contributes to CO₂ emissions without the use of carbon capture systems. This analysis comprehensively assesses hydrogen’s contribution to decarbonisation, encompassing the entire value chain: production methods, storage options (compressed gas, liquid hydrogen, and complex hydrides), transportation techniques (pipelines, cars, rail, and ammonia carriers), and various uses. Key performance parameters indicate trade-offs concerning energy density, storage, production expenses, and transportation alternatives. Notwithstanding advancements in hydrogen technologies, obstacles persist, encompassing energy penalties, infrastructural requirements, and safety issues. This evaluation highlights the need for coordinated policies and investment to enhance hydrogen’s adaptability, ensuring alignment with direct electrification policies to achieve net-zero emissions by 2050.

Magnesium-sulfur (Mg-S) batteries present a compelling energy storage solution, characterised by their remarkable theoretical energy density and economic viability. Nonetheless, challenges arise, including swift capacity degradation and suboptimal polysulfide (acting as an electronic and ionic insulator) utilisation, mainly due to a phenomenon known as the polysulfide "shuttle effect". This effect also leads to a decline in battery performance. The B3LYP functional and 6-311G (d, p) basis set were used to examine the optoelectronic and charge-transfer properties of a polyaniline-pyrrole (PANIPyr) composite, emphasising interatomic and electronic interactions that enhance charge transport and oxidation of MgS₂. The findings demonstrate the presence of coordination bonding between hydrogen in pyrrole and the N- ion in quinonediimine of polyaniline, significantly enhancing the electrical properties of PANI. The PANIPyr_P1 configuration exhibits the lowest Ɛgap and the highest charge-transfer capacity, thereby improving reactivity towards polysulfides in comparison to pure PANI. Significant electrical interactions at this site establish accessible electrophilic and nucleophilic regions that stabilise the ionic sides of the polysulfides, reduce the shuttle effect, and improve charge transport at the interface. PANIPyr_P1 demonstrates viability for minimising polysulfide migration and enhancing cathodic efficiency in Mg-S batteries, thereby laying a foundation for future investigations into polymer-based cathode modifiers.

Magnesium-sulfur (Mg-S) batteries constitute a novel category of multivalent energy storage systems, including enhanced theoretical energy density, material availability, and ecological compatibility. Notwithstanding these benefits, practical implementa-tion continues to be hindered by ongoing issues such as polysulfide shuttle effects, slow Mg²⁺ transport, and significant interfacial instability. This study emphasises recent progress in utilising transition metal chalcogenides (TMCs) as cathode materials and modifiers to overcome these challenges. We assess the structural, electrical, and cat-alytic characteristics of TMCs such as MoS₂, CoSe₂, WS₂, and TiS₂, highlighting their contributions to improving redox kinetics, retaining polysulfides, and enabling re-versible Mg²⁺ intercalation. The review synthesises results from experimental and theoretical studies to offer a thorough comprehension of structure-function interac-tions. Particular emphasis is placed on morphological engineering, modulation of electronic conductivity, and techniques for surface functionalisation. Furthermore, we examine insights from density functional theory (DFT) simulations that corroborate the observed enhancements in electrochemical performance and offer predictive di-rection for material optimisation. This paper delineates nascent opportunities in AI-enhanced materials discovery and hybrid system design, proposing future trajecto-ries to realise the potential of TMC-based Mg-S battery systems fully.