Tuning the microstructure of biomass-derived hard carbons by controlling the impurity removal process for enhanced Na ion storage performance

Mainstream hard carbon anode materials in sodium-ion batteries are frequently hindered by issues such as low kinetics for sodium-ion storage. In this work, we present a novel approach to overcome these key limitations by fluorine doping of wheat straw-derived hard carbon, which gives rise to a higher defect density, larger interlayer spacing and faster sodium-ion storage kinetics, when compared to the undoped hard carbon. As a result, the fluorine-doped hard carbon (HCF) exhibits an enhanced rate performance, higher specific capacity and optimized balance between slope and plateau capacity ratios, achieving a reversible capacity of 295 mAh g-1 at 1.0 A g-1. This study demonstrates that the intrinsic properties of hard carbon can be efficiently modified through heteroatom doping, offering a promising pathway for the development of high-performance anodes in sodium-ion batteries.

The battery is a storage medium for electrical energy for electronic devices developed effectively and efficiently. Sodium ion battery provide large-scale energy storage systems attributed to the natural existence of the sodium element on earth. The relatively inexpensive production costs and abundant sodium resources in nature make sodium ion batteries attractive to research. Currently, sodium ion batteries electrochemical performance is still less than lithium-ion batteries. The electrochemical performance of a sodium ion battery depends on the type of electrode material used in the manufacture of the batteries.. The main problem is to find a suitable electrode material with a high specific capacity and is stable. It is a struggle to increase the performance of sodium ion batteries. This literature study studied how to prepare high-performance sodium battery anodes through salt doping. The doping method is chosen to increase conductivity and electron transfer. Besides, this method still takes into account the factors of production costs and safety. The abundant coffee waste biomass in Indonesia was chosen as a precursor to preparing a sodium ion battery hard carbon anode to overcome environmental problems and increase the economic value of coffee grounds waste. Utilization of coffee grounds waste as hard carbon is an innovative solution to the accumulation of biomass waste and supports environmentally friendly renewable energy sources in Indonesia.

Molecular-scale controllable conversion of biopolymers into hard carbons towards lithium and sodium ion batteries: A review

Hard carbon/graphene microfibers as a superior anode material for sodium-ion batteries

As a new generation of high performance integrated energy storage battery system, the key factor in the development and application of sodium-ion batteries (SIBs) are the high-performance electrode materials. As a kind of hard carbon, the biomass-derived carbon has attracted much attention from experts and scholars due to the characteristics of rich-resource, low-cost and simple preparation process. It also can maintain the natural properties of biomass precursors, which contribute to the improvement of electrochemical performance. In the present work, cherry petals were used as precursors to prepare a hard carbon (CP) by a facile preparation. When it was used as an anode material for SIBs, CP exhibits high storage capacity with a high initial reversible capacity (310.2 mAh g-1), outstanding cyclic stability (the capacity retention rate was 99.3% after 100 cycles at 20 mA g-1) (Figure 1), favorable rate capability (146.5 mAh g-1, even at a very high current density of 500 mA g-1) and a high initial coulomb efficiency of 67.3%. In particular, approximate 45% of the capacity from CP is contributed by sodiation below 0.1 V (vs. Na+/Na). This low potential plateau makes CP energetically favorable as an anode material. The excellent electrochemical properties of CP can be attributed to its "open" lamellar structure-associated the nanoscale mesoporous, the presence of nitrogen/oxygen functional groups on the surface, and expanded interlayer distance (~0.44 nm) (Figure 2). Figure captions Figure 1. Cycling performance of CP (at 20 mA g-1). Figure 2. (a) HRTEM and SAED images of CP; (b) Contrast profiles along the arrows indicate interlayer distance of CP.

Biomass-derived hard carbon (HC) materials, celebrated for their superior sodium storage capability and economic viability, have emerged as a promising candidate for anode materials in sodium-ion batteries (SIBs). However, the electronic conductivity, cycling stability, and initial Coulombic efficiency (ICE) of HC materials remain significant challenges hindering their broader application. In this study, we successfully developed a HC anode material using Indian trumpetflower seeds (ITS) as precursors, enhanced by coating with pitch on their surface. This ITS-based HC material not only delivers an impressive reversible capacity of 430.3 mAh g-1 @ 300 mA g-1 but also maintains a capacity retention of 63% at a current density of 1500 mA g-1, along with a remarkable ICE of 90.92%. After 900 cycles, the capacity retention remains high at 77%, demonstrating exceptional cycling stability. These performance enhancements are attributed to the appropriate concentration of carbonized oxygen-doped pitch (CODP) coating, which avoids direct contact between the electrolyte and ITS and introduces oxygen atoms to provide more active sites. This work not only provides a promising precursor for the fabrication of high-performance HC anodes for SIBs but also introduces an innovative synthetic strategy, injecting momentum into the commercialization process of SIBs.

Hard carbon materials are considered as the most promising anode for sodium-ion batteries (SIBs). However, the high cost and poor rate performance hinder their application in SIBs. Moreover, the controversial mechanism of Na-ion storage restricts the improvement of hard carbon anodes. Herein, hard carbon micro-nano tubes (HCMNTs) from low-cost biomass kapok fibers are prepared as a promising anode for SIBs. Benefitting from the micro-nano structure, which offers low surface area and short Na+ diffusion path, 1400HCMNT possesses a good initial Coulombic efficiency of 80%, a high reversible capacity of 290 mA h g-1, and an excellent rate capacity. Furthermore, electron paramagnetic resonance and thermogravimetric analysis were applied to investigate the Na-ion storage mechanism in the HCMNTs. Sodium is stored in the hard carbon in an ionic state in the slope region and as quasi-liquid metallic sodium clusters in the low-voltage plateau.

Hard carbons have shown promising application potential as anode materials for sodium-ion batteries (SIBs), but adjusting the texture of hard carbons to manipulate their electrochemical behaviors remains a great challenge. In this work, a Cu-activation strategy is developed to control the defects of hard carbon nanofibers to achieve slope-reigned Na-ion storage behaviors. This method can effectively create defect-rich carbon texture by employing a small amount of Cu(NO3)2 as an activator but cannot induce an increase in the surface area. With the addition of the Cu activator, carbon nanofibers with increasing defects are synthesized by electrospinning and subsequent annealing. When carbon nanofibers are used as anodes for SIBs, their reversible capacity is increased with the increase of defects. Simultaneously, slope capacity gradually increases, while low-voltage plateau capacity reduces. Especially, the reversible capacity of Cu-activated nanofibers with more defects can be increased to 315 mA h g-1 with almost no plateau capacity compared with 203 mA h g-1 of inactivated nanofibers with a plateau capacity of 26%. Noticeably, the initial Coulombic efficiency (70%) of the activated nanofibers is just slightly lower than that (72%) of inactivated ones. The Cu-activated nanofibers also demonstrate superb rate performance and long cycle lifetime. Therefore, this work shows a new pathway for the design of defect-rich hard carbons with superior Na-ion storage performance.

Molecular-level precursor regulation strategy aids fast-charging hard carbon anodes for sodium-ion batteries

Hard carbon derived from sepals of Palmyra palm fruit calyx as an anode for sodium-ion batteries

Controlling the layered structure of WS2 nanosheets to promote Na+ insertion with enhanced Na-ion storage performance

Hard carbon stands as the most commercially viable anode material for sodium-ion batteries. Numerous studies confirm that closed nanopore design ensures the competitiveness of hard carbon compared to other anodes. However, the complex multi-scale microstructure of hard carbon poses challenges to the establishment of sodium storage mechanisms and quantitative relationships within closed nanopores. In this regard, closed nanopore engineering has been comprehensively summarized as a significant research direction in the field of hard carbon. Firstly, the sodium storage behavior of distinct nanopore types is compared. Subsequently, the structure and sodium storage behavior of closed nanopores are revealed through contact/non-contact techniques. Importantly, closed nanopore construction strategies are summarized based on their origins, which are divided into two categories: in situ formation and open nanopore conversion. Finally, perspectives on emerging frontiers are offered, including 3D pore topology visualization, defect modulation effects, multifield-coupled synthesis techniques, and the data-driven research paradigm for hard carbons. By synthesizing these advances and proposing a novel design framework, this review is anticipated to provide valuable insights for the design of high-performance hard carbon, thereby advancing the practical applications of sodium-ion batteries.

Sodium-ion batteries (SIBs) have significant potential for applications in portable electric vehicles and intermittent renewable energy storage due to their relatively low cost. Currently, hard carbon (HC) materials are considered commercially viable anode materials for SIBs due to their advantages, including larger capacity, low cost, low operating voltage, and inimitable microstructure. Among these materials, renewable biomass-derived hard carbon anodes are commonly used in SIBs. However, the reports about biomass hard carbon from basic research to industrial applications are very rare. In this paper, we focus on the research progress of biomass-derived hard carbon materials from the following perspectives: (1) sodium storage mechanisms in hard carbon; (2) optimization strategies for hard carbon materials encompassing design, synthesis, heteroatom doping, material compounding, electrolyte modulation, and presodiation; (3) classification of different biomass-derived hard carbon materials based on precursor source, a comparison of their properties, and a discussion on the effects of different biomass sources on hard carbon material properties; (4) challenges and strategies for practical of biomass-derived hard carbon anode in SIBs; and (5) an overview of the current industrialization of biomass-derived hard carbon anodes. Finally, we present the challenges, strategies, and prospects for the future development of biomass-derived hard carbon materials.

Regulating the structure of hard carbon derived from industrial waste to boost sodium storage performance.

Hard carbon (HC) has emerged as a promising anode material for sodium-ion batteries (SIBs) owing to its low cost, abundant renewable resources, and high specific capacity. However, its practical application is significantly hindered by the severe initial irreversible capacity loss resulting from sodium consumption during the first cycle. To address this issue, a variety of presodiation strategies have been developed to compensate for the sodium loss and improve the initial coulombic efficiency. In this review, recent advances in presodiation techniques for HC anodes are systematically summarized, including physical, short-circuit, electrochemical, and chemical presodiation approaches. The advantages and limitations of each method are also analyzed from the perspectives of safety, operability, and presodiation efficiency. Finally, the current challenges are outlined and future development directions are proposed to guide the development of efficient and scalable presodiation strategies for hard carbon anodes in practical Na-ion batteries.