Advancements and challenges in sodium-ion batteries: A comprehensive review of materials, mechanisms, and future directions for sustainable energy storage

The modern world has been significantly shaped by the development of battery technology, which have fueled improvements in EVs, portable gadgets, and renewable energy storage systems. The evolution of batteries has been characterized by constant innovation, starting with the early discovery of electrochemical principles in the late 18th century and continuing through the commercialization of lead-acid batteries in the 19th century. Although they solved difficulties of energy density and rechargeability, later innovations like nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries fell short in terms of efficiency and environmental sustainability [1], [2]. The advent of LIBs in the 1990s revolutionized energy storage with their high energy density, long cycle life, and lightweight nature. LIBs quickly became the cornerstone of portable electronics and the burgeoning EV market [3]. However, as the global demand for energy storage escalates, concerns about the sustainability, cost, and geopolitical concentration of Li resources have intensified, highlighting the need for alternative battery chemistries.

Energy storage technologies are crucial to addressing one of the most pressing problems of the twenty-first century: the transition to sustainable energy. Batteries play a central role in this paradigm shift, enabling decentralized energy systems, stabilizing grids, and powering the rapidly growing fleet of EVs. Moreover, the electrification of transportation and the proliferation of smart devices underscore the demand for scalable, cost-effective, and environmentally friendly battery technologies. While LIBs have dominated the market, their limitations—such as the scarcity of Li, ethical concerns over Co mining, and environmental hazards associated with their disposal—have prompted researchers to explore alternative technologies that can meet these demands without compromising sustainability [4], [5], [6].

SIBs have emerged as a promising alternative to LIBs, offering a sustainable and economically viable solution for large-scale energy storage applications. The appeal of SIBs lies in the abundance and uniform geographical distribution of Na, which contrasts sharply with the limited and geopolitically concentrated reserves of Li. Furthermore, the chemical similarities between Na and Li enable the adaptation of existing LIB manufacturing infrastructure for SIB production, potentially reducing the time and cost required for commercialization [7]. The novelty of current research on SIBs lies in overcoming the intrinsic challenges associated with Na, such as its larger ionic radius, higher reactivity, and lower energy density compared to Li. Recent advancements in material science, including the development of novel cathode and anode materials, have significantly improved the performance of SIBs, bringing them closer to commercial viability. For instance, layered oxides and polyanionic compounds have demonstrated promising electrochemical properties as cathodes, while hard carbon remains the most feasible anode material due to its cost-effectiveness and availability. Moreover, innovations in electrolyte and separator technologies have enhanced the stability and safety of SIBs, addressing critical barriers to their widespread adoption [8].

The significance of SIB research extends beyond the realm of energy storage to broader socioeconomic and environmental impacts. As the world transitions towards a low-carbon economy, the demand for grid-scale storage systems is projected to surge. SIBs, with their cost advantages and scalability, are ideally positioned to fulfill this demand. Additionally, SIBs have the potential to democratize energy access by reducing dependence on costly and scarce materials, making energy storage more accessible to developing regions. Comparatively, previous manuscripts on SIBs have primarily focused on specific components, such as cathode materials or electrolyte formulations, without providing a holistic perspective on the interdependence of these components. This review seeks to address this gap by offering a comprehensive analysis of the current state of SIB technology, highlighting recent advancements, challenges, and future directions. By integrating insights from diverse aspects of SIB research—ranging from material science to device engineering—this manuscript aims to provide a cohesive framework for understanding the potential of SIBs in the global energy landscape. Moreover, the timing of this research is critical. While LIBs continue to dominate the market, their limitations are becoming increasingly apparent, particularly in the context of global resource constraints and environmental considerations [9], [10].

In contrast to earlier reviews, which often emphasize the challenges associated with SIBs, this manuscript adopts a balanced approach by exploring both the limitations and the innovative solutions being developed to address them. For example, while the larger ionic radius of Na poses challenges for intercalation into host materials, recent studies have demonstrated that optimizing material morphology and structure can mitigate these effects. Similarly, while the energy density of SIBs remains lower than that of LIBs, their superior performance in terms of cost, safety, and sustainability makes them highly competitive for specific applications. This review also seeks to highlight underexplored areas of SIB research, such as the role of organic and hybrid materials in enhancing battery performance, the potential of novel electrolyte systems to improve ionic conductivity and stability, and the integration of SIBs with renewable energy systems. By synthesizing the latest research findings and identifying emerging trends, this manuscript aims to provide a comprehensive resource for researchers, policymakers, and industry stakeholders.

As the global energy landscape evolves, SIBs are poised to play a crucial role in enabling the transition to a more sustainable and equitable energy system. Their potential applications extend beyond grid storage to include electric mobility, backup power systems, and off-grid solutions. The development of SIBs also aligns with broader efforts to diversify energy storage technologies, reducing reliance on any single chemistry and enhancing the resilience of supply chains. As research continues to address the technical and economic challenges associated with SIBs, their integration into the global energy infrastructure is becoming increasingly feasible. This review aims to provide a roadmap for realizing this vision by synthesizing current knowledge, identifying key challenges, and proposing actionable solutions.