Ion migration refers to the process of ions moving within a medium driven by an external electric field or a chemical gradient. The prerequisite for the implementation of ion migration technology lies in the construction of suitable electrodes, electrolytes, and media [1,2,3,4,5]. Currently, ion migration technology is primarily applied in emerging energy storage and conversion devices [6,7,8,9]. Examples include supercapacitors, which store and release energy through charge adsorption and ion migration [10,11,12,13,14,15,16,17,18,19], and fuel cells based on ion exchange technology, where ions conduct for energy conversion [20,21,22,23,24,25,26,27,28,29]. In addition, ion batteries, based on the migration and insertion/extraction processes of ions in electrolytes and electrode materials, are among the most widely used and advanced energy storage devices.

Group-IV materials, due to their abundant raw materials, low production costs, non-toxic nature, and excellent electrochemical properties, serve as ideal anode materials for various ion migration-based batteries [30,31,32]. Over the past few decades, in addition to traditional amorphous carbon and graphite, various carbon materials like graphene and graphdiyne (GDY), as well as other Group-IV materials such as silicene, germanene, and tin have become well known. These materials not only differ in morphology and dimensions but also exhibit distinct local electronic structures [33,34,35]. Hence, a comprehensive understanding of the energy storage properties of various carbon materials still requires further research. Group-IV materials, as crucial components of ion migration-driven energy storage technologies, have been a focal point of research for decades. Various studies encompass the design and fabrication of rational structures, as well as selecting metal ions with different valence states (Li⁺, Na⁺, K⁺, Zn²⁺, Mg²⁺, Al³⁺, etc.) to enhance the performance of ion batteries [36,37,38,39,40,41,42].

At the same time, exploring new mechanisms for ion migration-driven batteries is crucial for the application of battery technology in green, cost-effective, and large-scale energy storage and conversion [43,44]. In comparison to chemical energy storage systems in which ion batteries achieve energy conversion through ion migration, novel self-powered batteries based on carbon materials have gradually emerged through external stimuli, with moisture-enabled electricity generation (MEG) being the most significant among them [45]. This technology, serving as an innovative green energy harvesting technique, harnesses the interactions between carbon materials and ubiquitous atmospheric moisture to directly generate electrical energy. The electricity generation process relies on the dynamic adsorption and desorption of moisture and the migration of ions. Since moisture serves as the sole external source, this electricity generation process is highly environmentally friendly, with no pollutants produced, and is highly reversible. It can be viewed as an efficient, green, ion migration-driven battery for the next generation.

Alkali metal ion batteries have garnered significant attention from scholars both domestically and internationally in recent years due to their promising prospects in large-scale electrochemical energy storage. Carbon materials, exemplified by graphene and carbon nanotubes, stand out for their unique structural characteristics, offering excellent conductivity and environmentally friendly, non-toxic attributes. These qualities make them essential electrode materials for the negative terminals of alkali metal ion batteries. The most representative alkali metal ionic batteries include lithium-ion batteries (LIBs), sodium-ion batteries (NIBs), and potassium-ion batteries (KIBs). Among these, LIBs were the first to be commercialized and are known for their higher capacity and power density compared to other early commercial batteries. 

Porous carbon materials have attracted widespread attention in the field of LIBs due to their high specific surface area, pore volume, low density, and excellent chemical stability, especially their multi-level pore size advantages [46]. When used as the anode in LIBs, their high specific surface area allows them to accommodate a greater number of lithium ions, providing high capacity for LIBs. Wang et al. [47] fabricated porous carbon with a substantial specific surface area through the direct carbonization of bovine bone at 1100 °C. This process yielded PC-1100, a highly defective porous carbon material, which demonstrated remarkable attributes: a specific surface area of 2096 m² g⁻¹, a maximum mesopore volume of 1.829 cm³ g⁻¹, a tightly distributed mesopore size around 4.0 nm, and excellent electrical conductivity at 5141 S m⁻¹. In their research, PC-1100 was assessed as a negative electrode in LIBs, showcasing an impressive reversible capacity of 1488 mAh g⁻¹ after 250 cycles at 1 A g⁻¹, and 661 mAh g⁻¹ after 1500 cycles at 10 A g⁻¹. The multi-dimensional complex pore structure offers effective pathways for the diffusion of lithium ions and shorter distances for lithium ion diffusion. In a related study, Qu et al. [48] introduced a method for synthesizing two-dimensional (2D) stratified porous carbon (HPC) using soft asphalt as a carbon source, oyster shell as a template, and an activated precursor. When employed as an electrode material in LIBs, HPC demonstrated a remarkable reversible capacity of 1251 mAh g⁻¹ at 0.1 A g⁻¹ and exhibited outstanding cyclic stability. These findings underscore the effectiveness of the 2D layered structure in shortening the solid-state diffusion distance of lithium ions during the charge and discharge processes of LIBs. Defects such as vacancies and doping with heteroatoms can serve as sites for lithium storage. Liu et al. [49] introduced an efficient method for synthesizing Co_n@N-C hybrids (i.e, Co@N-C-0, Co_n@N-C-1, and Co_n@N-C-2), characterized by interconnected porous carbon nanostructures and numerous active sites like Co-N-C. When evaluated as an anode material for LIBs, Co_n@N-C-1 showed remarkable lithium storage performance, starting with an initial reversible capacity of 1587 mAh g⁻¹ at 0.1 C and maintaining a high reversible capacity of 1000 mAh g⁻¹ at 5 C after 800 cycles. Both experimental and theoretical results validate the significant role of Co-N-C, with its high specific activity, in facilitating the transport and storage of Li⁺ within interconnected porous carbon nanostructures. Consequently, porous carbon demonstrates superior electrochemical properties compared to conventional graphite carbon and has found successful application in ion batteries. As a result, porous carbon often exhibits better electrochemical performance than traditional graphite carbon and has been successfully applied in ion batteries.

Carbon nanotubes (CNTs) consist of single or multiple coaxial layers of carbon sheets, forming a material with a microstructure akin to that of graphite layers. This intricate microstructure enables a shallow penetration of alkali metal ions, shorter migration distances, and multiple insertion sites (including gaps and interlayer spaces) within the tubes and between the layers [50,51,52]. Moreover, due to the excellent electrical conductivity of CNTs and doped CNTs, they exhibit robust electronic conduction and efficient ion transport capabilities, thus establishing them as exemplary anode materials for LIBs. For example, Peng et al. [53] meticulously documented the development of vertically aligned nitrogen-doped core-sheath carbon nanotube (N-CNT) films for use as flexible anodes in LIBs. These N-CNT films exhibited outstanding tensile strength (690 MPa) and electrical conductivity (410 S cm⁻¹). Furthermore, even under the demanding conditions of a 4C rate, these films displayed exceptional high capacity of 390 mAh g⁻¹, retaining 97% of this capacity after enduring 200 cycles. This highlights the advantages of carbon nanotubes in LIBs.

Typical carbon electrodes include a 2D structure composed of carbon atoms, with graphene as a representative example. Graphene exhibits a high lithium storage capacity and an open porous structure that offers a low-energy barrier pathway for electrolyte ions, ensuring excellent rate capability [54,55]. Baek et al. [56] prepared edge-functionalized graphene nanosheets (GnPs) with thiolactic acid (TA) via a ball-milling method. These GnPs exhibited a low average working voltage (<0.5 V) and exceptional rate performance (>0.5 A g⁻¹) as an anode material for LIBs. Researchers believe that the high specific capacity of graphene primarily arises from the presence of abundant edge defects and excellent electrical conductivity, resulting in an electrode film resistance of only 10~1000 Ω sq⁻¹. Therefore, designing specific microstructures of graphene holds significant importance for enhancing the specific capacity of LIBs. Sun et al. [57] introduced a novel method for producing 3D edge-curled graphene (3D ECG) and conducted half-cell tests using lithium to demonstrate its outstanding electrochemical performance. The specific capacities measured were 907.5 mAh g⁻¹ at a current density of 0.05 A g⁻¹ and 347.8 mAh g⁻¹ at 5.0 A g⁻¹. Similar to graphene, GDY shares hybrid carbon atoms and boasts a distinctive p-conjugated carbon framework with a 2D expanded structure. Huang et al. [58] synthesized chlorographdiyne (Cl-GDY) through a Glaser–Hay coupling reaction on copper foil. This bottom-up preparation of Cl-GDY, combined with its robust chemical functionalization capability using alkyl monomers, yields a carbon skeleton with a substantial and evenly distributed presence of substituted chlorine atoms. These chlorine atoms possess suitable electronegativity and atomic size, enabling them to collaboratively and steadfastly accommodate lithium within the Cl-GDY skeleton. Consequently, this process creates a greater number of lithium storage sites. With the increasing commercialization of ion batteries, there is a growing interest in NIBs and KIBs due to cost-effectiveness and raw material availability considerations. The unique structural characteristics of carbon electrodes offer effective solutions to the challenges posed by the larger atomic radii and higher relative molecular mass of sodium and potassium ions. For instance, Xu et al. [59] developed a composite material with a yolk-shell structure (G@Y–SFeS₂@C) on a graphene substrate, incorporating FeS₂. This composite material offers excellent electrical conductivity and ample internal void space to accommodate the volume expansion of FeS₂. Palermo et al. [60] reported the fabrication of a nanostructured graphene anode for Na⁺ storage, which includes Janus graphene, featuring functionalized stacked graphene sheets on one side. Zhang and co-workers uniformly grew Fe₂VO₄ nanoparticles (FVO) on highly conductive reduced graphene oxide (rGO) through solvent-thermal treatment followed by annealing. This resulted in the formation of a conductive network (FVO/rGO) conducive to Na⁺ migration and storage [61]. GDY, as a representative 2D carbon material, also plays a pivotal role in enhancing NIBs and KIBs, owing to its distinctive conjugated structure. Sun et al. [62] employed first principle calculations to estimate the intrinsic storage capacity of potassium ions in GDY, revealing a remarkably high value of up to 620 mAh g⁻¹, a substantial improvement compared to graphite’s capacity of 278 mAh g⁻¹. Subsequent experimental evaluations confirmed the outstanding electrochemical performance of the prepared GDY framework when used as a KIB anode, exhibiting a robust specific capacity of approximately 505 mAh g⁻¹ at 50 mA g⁻¹. Additionally, it demonstrated exceptional rate capability (150 mAh g⁻¹ at 5000 mA g⁻¹) and impressive cycle stability, with a capacity retention rate exceeding 90% after 2000 cycles at 1000 mA g⁻¹. Huang et al. [63] designed a sodium-ion electrode based on unique conjugated structure of boron-GDY. Boron-GDY boasts a distinctive conjugated structure, featuring an sp-hybrid carbon skeleton and uniformly distributed boron heteroatoms on the 2D molecular plane. The unconventional bonding environment created by the full sp-carbon framework and the electron-deficient boron centers enhances the affinity for metal atoms, thereby offering additional binding sites for efficient ion storage. Furthermore, the expanded molecular pore within the Boron-GDY molecular plane facilitates the vertical transfer of metal ions, further improving its performance as an electrode material. This exemplifies another typical application of GDY and its derivatives in ion batteries. In addition to conventional graphene and GDY, other carbon materials with porous structures have notably enhanced the performance of low-valence ion batteries. Lu et al. [64] introduced a layered structure of nitrogen-doped carbon microspheres (CMSs). This structure not only offers more active sites but also mitigates the volume expansion caused by potassium ion insertion. As an anode material for PIBs, CMSs demonstrated impressive reversible discharge capacities of 328 and 125 mAh g⁻¹ at 100 and 3000 mA g⁻¹, respectively. Furthermore, Lu et al. [65]. developed a MoSe_2/N-C KIB using 1 M potassium bis(fluoro-sulfonyl) imine in ethyl metal carbonate as an electrolyte. The negative electrode material comprises a MoSe2/N-C composite coated with carbon-coated MoSe₂ nanosheets. K⁺ insertion induces a phase transition in MoSe₂, leading to the formation of Mo₁₅Se₁₉ during charging and K₅Se₃ as the final discharge product. After 300 cycles at 100 mA g⁻¹, the MoSe₂/N-C KIBs exhibited a reversible capacity of 258.02 mA h g⁻¹, with a Coulombic efficiency close to 100%. This showcases excellent rate performance and long-cycle stability.

The relative scarcity of metal resources, with lithium as a representative, and their uneven global distribution have constrained the rapid development of monovalent metal-ion batteries. Therefore, the development of low-cost, high-safety, and high-energy-density carbon-based ion batteries is crucial for the future of energy storage. Multivalent metal batteries, such as magnesium ion batteries, zinc ion batteries, and aluminum ion batteries, have emerged in recent years as highly promising next-generation secondary batteries.

Magnesium ion batteries using carbon electrodes have brought new possibilities for battery technology due to their high bulk energy density and absence of dendrite problems. The use of carbon electrodes in magnesium ion batteries has opened up exciting possibilities in battery technology. These carbon materials, particularly graphene, a 2D nanomaterial, have proven effective in addressing dendrite-related issues during ion migration in magnesium ion batteries. In their research, Xu et al. [66] utilized fluorine-doped graphene nanosheets (FGS) as electrode materials for MIBs. They observed that the FGS electrode exhibited a specific capacity of 100 mAh g⁻¹ at a current density of 10 mA g⁻¹ when cycled from 0.5 V to 2.75 V in MgClO₄-DMSO electrolyte. This unique Mg/FGS system operates through a preceding anion process, followed by reversible cation storage. The reduction in charge density due to the formation of large-sized monovalent complex cations and the easy accessibility to surface redox sites contribute to minimal voltage polarization, with minimal MgF₂ nucleation. The distinctive structure of carbon materials not only facilitates ion migration but also provides a platform for coating and supporting other materials, thereby enhancing material conductivity and optimizing magnesium ion battery performance. In a separate study by Chi et al. [67], a cathode material for MIBs was developed using nickel-doped titanium dioxide bronze coated with redox graphene and carbon nanotubes (rGO@CNT). At a current density of 100 mA g⁻¹, the discharge specific capacity of NT-2/rGO@CNT reached an impressive 167.5 mAh g⁻¹, which is 2.36 times that of pure TiO₂-B. Another notable development is the use of a binder-free polyaniline array/carbon cloth (PANI/CC) as the electrode material for MIBs by An et al. [68]. The incorporation of carbon cloth significantly enhances the electrode’s conductivity and mitigates ion agglomeration. Comparatively, this electrode exhibits improved chemical performance when compared to a pure PANI electrode. The PANI/CC cathode demonstrates the highest specific capacity of 219 mA h g⁻¹ at 200 mA g⁻¹, with an outstanding capacity retention rate of 97.25% even after more than 1500 cycles at 1 A g⁻¹.

Combining zinc ions with carbon electrodes to fabricate ion batteries highlights the potential of this technology due to its low manufacturing cost, enhanced safety, and excellent recyclability [69,70,71]. Especially in Zinc-ion batteries (ZIBs), the use of water electrolytes has shown great potential for portable electronic applications and large-scale energy storage systems. Qu et al. [72] prepared in situ cathode materials for water-containing fast-charging and ultra-stabilized Zn-I₂ batteries, which exhibited a capacity of 90 mAh g⁻¹ at 5 A g⁻¹ and a superior long-cycle life close to 39,000 cycles with a capacity retention of 80.6% after a series of rate tests from 0.2 to 5 A g⁻¹. This excellent performance is attributed to the ideal mesoporous carbon structure, which shortens the ionic and electronic diffusion paths and can confine the polyiodide compound/iodine conversion reaction inside the mesopore. In addition, carbon materials not only provide traditional optimization strategies but also bring new hope for the development of intelligent ion batteries. For example, Qu et al. [73] have designed a powerful Zn-air battery, utilizing a graphene-coated sponge as a pressure-sensitive air cathode, enabling the ion battery to autonomously control energy output.

Aluminum-ion batteries (AIBs) have garnered significant interest due to their higher valency, cost-effectiveness, and non-flammable nature. Nonetheless, akin to other ion-based batteries, the transport and storage of Al³⁺ within the electrode material pose formidable challenges, impeding the advancement of Al-ion batteries. Carbon materials present a promising avenue for enhancing Al-ion battery performance due to their distinctive structure. As an illustration, Wu et al. [74] demonstrated the facile fabrication of nanoporous, densely stacked films using three-dimensional (3D) graphene aerogel. This was achieved through the rapid reduction of GO aerogel via self-propagating combustion within a matter of seconds. This material was employed as an advanced, binder-free cathode for high-capacity AIBs with ultra-fast performance. Owing to the exceptional attributes of the graphene aerogel-derived dense film, including its 3D nanoporous structure, substantial surface area (513 m² g⁻¹), high electrical conductivity (581 S cm⁻¹), dense packing (0.61 g cm⁻³), and expanded interlayer spacing (3.69 Å), the assembled AIBs exhibited a significantly higher capacity (245 mAh g⁻¹) at 1 A g⁻¹, surpassing that of AIB graphite by a factor of two. Furthermore, Yu et al. [75] introduced a thermal reductive perforation TRP method. In this procedure, the thermal decomposition of the block copolymer generates reactive radicals that react with oxygen, resulting in the production of graphene fragments. This material exhibits a three-layer structure with in-plane nanopores, an interlayer spacing expanded by over 50%, and oxygen content similar to that of graphene following high-temperature annealing. When employed as an AIB cathode, it achieved a reversible capacity of 197 mAh g⁻¹ at a current density of 2 A g⁻¹, representing 92.5% of the theoretical capacity projected by density flood theory simulations. Cai et al. [76] synthesized a composite of converted FeF₃-expanded graphite (EG) with favorable electrical conductivity and cyclability for use as a cathode material in AIBs. The enhanced interaction between expanded graphite and FeF₃ resulted in increased electrical conductivity of FeF₃, improving interfacial charge transfer and boosting the thermodynamics and kinetics of FeF₃ nanoparticles for Al³⁺ insertion. As a result, the AIB demonstrated a satisfactory reversible specific capacity of 266 mAh g⁻¹ at 60 mA g⁻¹ after 200 cycles, along with a Coulombic efficiency of nearly 100% after 400 cycles at a current density of 100 mA g⁻¹.

Moreover, beyond single-metal ion batteries, there are bimetallic ion batteries, such as Li⁺/Mg²⁺ hybrid-ion batteries (LMIBs), which combine the advantages of LIBs and MIBs. Zhao et al. [77] presented an oxygenated MoS₂ nanoconjugation (O-MoS₂/G) anchored on graphene. Their study demonstrated that the intercalation behavior of Li⁺ facilitates the intercalation kinetics of Mg²⁺, and the insertion of Li⁺ into MoS₂ reduces the Mg²⁺ migration energy barrier. The O-MoS₂/G exhibited superior rate capability and cycling performance, maintaining a reversible capacity of 123.3 mAh g⁻¹ after 2000 charge–discharge cycles at 1000 mA g⁻¹.

At present, the reversible specific capacity of C negative electrode materials is close to the theoretical specific capacity of 372 mAh g⁻¹. Therefore, in order to improve the energy density of LIBs, it is necessary to develop negative electrode materials with higher specific capacity. Materials based on Group-IV elements (Si, Ge, Sn) possess high capacity, and extensive research has been conducted on their utilization as replacements for carbon-based electrodes in ion batteries.

Elemental Si and C share similar structures and chemistry, making materials like siloxane, akin to graphene, a valuable choice in designing electrodes for ion batteries. The key to silicon-based materials is nano-dispersion, such as the preparation of nanosheets of silicon, which effectively reduces surface stresses and thus alleviates volume expansion problems. Feng et al. [78], for instance, developed 2D pre-lithiated siloxane nanosheets with a high Initial Coulombic Efficiency (ICE) for use as lithium-ion anodes. These nanosheets were obtained through chemical pre-lithiation and demonstrated a meticulously controlled uniform layered structure. Subsequently, by immersing the anode in a lithiation reagent, they generated siloxanes with a high ICE. They assembled a high-energy-density battery by using a pre-lithiated siloxane anode and a 5 V-class LiNi_0.5Mn_1.5O₄ cathode, which exhibited improved cycling performance and retained 94.3% of its capacity after 200 cycles.

The silicon electrode typically undergoes significant volumetric changes (ranging from 300% to 400%) during the metal ion insertion/extraction process. Consequently, this leads to the pulverization of the active material, continuous generation of the solid electrolyte interface (SEI) layer, poor contact between the active material and the current collector, as well as a low initial Coulombic efficiency (ICE). These severe deteriorations have a substantial impact on the practical application of silicon negative electrodes. Lou et al. [79] engineered freestanding silicon-graphene electrodes, known as 3D-printed grid-like silicon-graphene (3D-Si/G) electrodes, through the use of 3D printing technology to control the electrode’s structure. This innovative design integrated numerous layered pores and 3D porous scaffolds, effectively addressing volume expansion and contraction concerns linked to silicon anodes. Additionally, the rGO network expedited electron-ion transfer, accelerating electrochemical reaction kinetics. Consequently, the optimized 3D-Si/G-1 electrode achieved an exceptionally high surface capacity of 16.2 mAh cm⁻².