A Review on Electrode Materials of Fast-Charging Lithium-Ion batteries

Scotch Pine Cones-Derived Hard Carbon as an Anode Material for Sodium-Ion Battery Applications

A biobased anode material for sodium-ion batteries (SIBs) was prepared through the simple pyrolysis of Scotch pine cones (Pinus sylvestris, SPC), followed by a heteroatom doping modification. The resulting nitrogen-doped hard carbon exhibited a high reversible capacity of 273 mA·h·g-1 at a current density of 25 mA·g-1 compared to the undoped material (197 mA·h·g-1). X-ray diffraction analysis shows that the produced hard carbon from the biomass is highly amorphous in nature, and high-resolution transmission electron microscopy images reveal the presence of localized graphite-like structures that are found to be beneficial for the storage and transport of Na+ ions during charging/discharging. Experimental results demonstrated that the increased specific surface area (S BET = 424 m2·g-1), high micropore volume (0.177 cm3·g-1), and expanded interlayer spacing (>3.7 Å) and a high Na+-ion diffusion coefficient (3.08 × 10-16 cm2·s-1) facilitated the diffusion of sodium ions, leading to a high capacity retention of 80% after 250 cycles for the SPC-N material over the undoped one, SPC (71%). This study highlights the potential of low-cost, widely available biobased Scotch pine cones as an alternative anode material to enhance the sustainability of SIB production.

Machine learning-assisted design and prediction of materials for batteries based on alkali metals

Since the commercialization of lithium-ion batteries in the 1990s, batteries based on alkali metals have been promising candidates for energy storage. The performances of these batteries, in terms of cost-efficiency, energy density, safety, and cycle life need continuous improvement. Battery performances are highly dependent on electrode materials, yet the long experimental period, intensive labor, and high cost remain bottlenecks in the improvement of electrode materials. Machine learning (ML), which is being increasingly integrated into materials science, offers transformative potential by reducing the R&D period and cost. ML also demonstrates significant advantages in the performance prediction of various materials, and it can also help reveal the structure-performance relationship of materials. ML-assisted material design and performance prediction thus enable the innovation of advanced materials. Herein, implementation of ML for exploring alkali metal-based batteries is outlined, highlighting various ML algorithms as well as electrode reaction mechanisms.

N, P Co-Doped Hard Carbon Anodes for High-Performance Lithium-Ion Batteries with Enhanced Capacity Retention and Cycle Stability

Compared to the traditional graphite anode, heteroatom-doped polymer carbon materials have high capacity retention due to their high porosity and porous structure. Therefore, they have great potential for application in lithium-ion battery (LIB) anodes. In this work, an N, P co-doped precursor polymer material (MBPp), synthesized via a one-pot method using bisphenol-A (C-source), melamine (N-source), and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (P-source). The resulting N, P-co-doped hard carbon materials (MBPs) were prepared at various pyrolysis temperatures, yielding microporous, mesoporous, and macroporous structures. MBP materials demonstrated excellent electrochemical performance as LIB anodes. Notably, MBP-900 achieved a reversible capacity of 262 mAh g-1 at 1000 mA g-1 (in 0.005-2.0 V voltage range) with a capacity retention rate of 97.1 % after 1000 cycles. These findings highlight the significance of MBP materials, which possess numerous defects, large layer gaps, and excellent cycle stability, in advancing the development of polymer anode materials for LIBs.

In-Situ Constructing N,S-Codoped Carbon Heterointerface for High-Rate Cathode of Sodium-Ion Batteries

Na3V2(PO4)3 (NVP) is considered one of the promising choices for cathodes of sodium-ion batteries, but the poor conductivity resulted inferior rate performance limited the practical development of NVP cathodes. In this study, we successfully synthesized N/S dual-atom doped carbon coatings in situ through a simple one-step solid-state sintering method. The uniformly coated carbon layer can inhibit the agglomeration and growth of active materials during the sintering process, shorten the Na+ migration path, and increase the contact area with the electrolyte, thus facilitating rapid Na+ migration. Notably, the doping of N elements can alter the electron distribution of carbon coating, enhancing electron conductivity. Furthermore, the introduction of S elements in the carbon layer can induce the formation of stable C-S-C bonds in the molecular layer, expanding the interlayer spacing, which is beneficial for Na+ transport and storage. Therefore, the modified NVP@NSC composite provides a high specific capacity of 90.3 mAh g-1 at a rate of 20 C, with a capacity retention rate of 94.4% after 8000 cycles, demonstrating excellent stability at high current densities. Moreover, the full cell exhibits remarkable electrochemical performance at 5 C. This research contributes to the practical development of NVP cathodes.

Insights into the Deterioration Mechanism of Charging Ability during Calendar Aging and Cycling Aging of High-Voltage Co-Poor NCM Cathode-Graphite Full Battery

Lithium-ion battery (LIB) has gained significant recognition for the power cell market owing to its impressive energy density and appealing cost benefit. Among various cathodes, a high-voltage cobalt-poor lithium nickel manganese cobalt oxide cathode (Co-poor NCM cathode) has been considered as a promising strategy to enhance its energy density. Despite these advantages, high-voltage Co-poor NCM cathode-graphite full battery usually suffers from poor rate performance. However, fast charging has been a key indicator for widespread application of power batteries. Although many efforts have been made to improve the charging performance of fresh batteries, few works investigate the charging ability during calendar aging and cycling aging of high-voltage Co-poor NCM cathode-graphite full battery. In this work, we found that the charging ability becomes worse during calendar aging and cycling aging. Results showed that the increasing charge transfer resistance from the cathode is the major obstacle to achieving fast charging during the aging process. To address the problem, high-voltage Al2O3-coated Co-poor NCM cathode successfully prepared via a simple atomic layer deposition (ALD) method has been developed to reduce the decay of charging performance during calendar aging and cycling aging. Al2O3-coated NCM cathode can effectively reduce the growth rate of the resistance of cathode, which is benefiting from the conversion of Al2O3 into LiAlO2 with high ionic conductivity and the restriction formation of rock salt phase. Benefiting from the decreased charge transfer resistance of the NCM cathode, the mismatch of the lithium-ion reaction kinetics is well alleviated, thus effectively reducing the polarization under fast charging. As a result, Al2O3-coated NCM cathode-graphite full battery shows the slow deterioration of charging performance during the aging process. This work provides a promising strategy for constructing fast-charging batteries during calendar aging and cycling aging.

From Lab to Application: Challenges and Opportunities in Achieving Fast Charging with Polyanionic Cathodes for Sodium-Ion Batteries

Sodium-ion batteries (SIBs), recognized for balanced energy density and cost-effectiveness, are positioned as a promising complement to lithium-ion batteries (LIBs) and a substitute for lead-acid batteries, particularly in low-speed electric vehicles and large-scale energy storage. Despite their extensive potential, concerns about range anxiety due to lower energy density underscore the importance of fast-charging technologies, which drives the exploration of high-rate electrode materials. Polyanionic cathode materials are emerging as promising candidates in this regard. However, their intrinsic limitation in electronic conductivity poses challenges for synchronized electron and ion transport, hindering their suitability for fast-charging applications. This review provides a comprehensive analysis of sodium ion migration during charging/discharging, highlighting it as a critical rate-limiting step for fast charging. By delving into intrinsic dynamics, key factors that constrain fast-charging characteristics are identified and summarized. Innovative modification routes are then introduced, with a focus on shortening migration paths and increasing diffusion coefficients, providing detailed insights into feasible strategies. Moreover, the discussion extends beyond half cells to full cells, addressing challenges and opportunities in transitioning polyanionic materials from the laboratory to practical applications. This review aims to offer valuable insights into the development of high-rate polyanionic cathodes, acknowledging their pivotal role in advancing fast-charging SIBs.

Stable cycling and low-temperature operation utilizing amorphous carbon-coated graphite anodes for lithium-ion batteries

With the continuous expansion of the lithium-ion battery market, addressing the critical issues of stable cycling and low-temperature operation of lithium-ion batteries (LIBs) has become an urgent necessity. The high anisotropy and poor kinetics of pristine graphite in LIBs contribute to the formation of precipitated lithium dendrites, especially during rapid charging or low-temperature operation. In this study, we design a graphite coated with amorphous carbon (GC) through the Chemical Vapor Deposition (CVD) method. The coated carbon layer at the graphite interface exhibits enhanced reaction kinetics and expanded lithium-ion diffusion pathways, thereby reduction in polarization effectively alleviates the risk of lithium precipitation during rapid charging and low-temperature operation. The pouch cell incorporating GC‖LiCoO2 exhibits exceptional durability, retaining 87% of its capacity even after 1200 cycles at a high charge/discharge rate of 5C/5C. Remarkably, at -20 °C, the GC-2 maintains a specific capacity of 163 mA h g-1 at 0.5C, higher than that of pristine graphite (65 mA h g-1). Even at -40 °C, the GC-2‖LiCoO2 pouch cell still shows excellent capacity retention. This design realizes the practical application of graphite anode in extreme environments, and have a promising prospect of application.

Boosting the interfacial dynamics and thermodynamics in polyanion cathode by carbon dots for ultrafast-charging sodium ion batteries

Ultrafast-charging is the focus of next-generation rechargeable batteries for widespread economic success by reducing the time cost. However, the poor ion diffusion rate, intrinsic electronic conductivity and structural stability of cathode materials seriously hinder the development of ultrafast-charging technology. To overcome these challenges, an interfacial dynamics and thermodynamics synergistic strategy is proposed to synchronously enhance the fast-charging capability and structural stability of polyanion cathode materials. As a case study, a Na3V2(PO4)3 composite (NVP/NSC) is successfully obtained by introducing an interface layer derived from N/S co-doped carbon dots. Density functional theory calculations validate that the interfacial bonding effect of V-N/S-C significantly reduces the Na+ transport energy barrier. D-band center theory analysis confirms the downward shift of the V d-band center enhances the strength of the V-O bond and considerably inhibits irreversible phase transformation. Benefitting from this interfacial synergistic strategy, NVP/NSC achieves a high capability and excellent cycling stability with a surprisingly low carbon content (2.23%) at an extremely high rate of 100C for 10 000 cycles (87.2 mA h g-1, 0.0028% capacity decay per cycle). Furthermore, a superior performance at 5C (115.3 mA h g-1, 92.1% capacity retention after 800 cycles) is exhibited by the NVP/NSC‖HC full cell. These findings provide timely new insights for the systematic design of ultrafast-charging cathode materials.

State-of-the-Art Review on Amorphous Carbon Nanotubes: Synthesis, Structure, and Application

Carbon nanotubes (CNTs) have rapidly received increasing attention and great interest as potential materials for energy storage and catalyst fields, which is due to their unique physicochemical and electrical properties. With continuous improvements in fabrication routes, CNTs have been modified with various types of materials, opening up new perspectives for research and state-of-the-art technologies. Amorphous CNTs (aCNTs) are carbon nanostructures that are distinctively different from their well-ordered counterparts, such as single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs, respectively), while the atoms in aCNTs are grouped in a disordered, crystalline/non-crystalline manner. Owing to their unique structure and properties, aCNTs are attractive for energy storage, catalysis, and aerospace applications. In this review, we provide an overview of the synthetic routes of aCNTs, which include chemical vapor deposition, catalytic pyrolysis, and arc discharge. Detailed morphologies of aCNTs and the systematic elucidation of tunable properties are also summarized. Finally, we discuss the future perspectives as well as associated challenges of aCNTs. With this review, we aim to encourage further research for the widespread use of aCNTs in industry.

Emerging Multiscale Porous Anodes toward Fast Charging Lithium-Ion Batteries

With the accelerated penetration of the global electric vehicle market, the demand for fast charging lithium-ion batteries (LIBs) that enable improvement of user driving efficiency and user experience is becoming increasingly significant. Robust ion/electron transport paths throughout the electrode have played a pivotal role in the progress of fast charging LIBs. Yet traditional graphite anodes lack fast ion transport channels, which suffer extremely elevated overpotential at ultrafast power outputs, resulting in lithium dendrite growth, capacity decay, and safety issues. In recent years, emergent multiscale porous anodes dedicated to building efficient ion transport channels on multiple scales offer opportunities for fast charging anodes. This review survey covers the recent advances of the emerging multiscale porous anodes for fast charging LIBs. It starts by clarifying how pore parameters such as porosity, tortuosity, and gradient affect the fast charging ability from an electrochemical kinetic perspective. We then present an overview of efforts to implement multiscale porous anodes at both material and electrode levels in diverse types of anode materials. Moreover, we critically evaluate the essential merits and limitations of several quintessential fast charging porous anodes from a practical viewpoint. Finally, we highlight the challenges and future prospects of multiscale porous fast charging anode design associated with materials and electrodes as well as crucial issues faced by the battery and management level.

MOF-Derived Nitrogen-Doped Porous Carbon Polyhedrons/Carbon Nanotubes Nanocomposite for High-Performance Lithium-Sulfur Batteries

Nanocomposites that combine porous materials and a continuous conductive skeleton as a sulfur host can improve the performance of lithium-sulfur (Li-S) batteries. Herein, carbon nanotubes (CNTs) anchoring small-size (~40 nm) N-doped porous carbon polyhedrons (S-NCPs/CNTs) are designed and synthesized via annealing the precursor of zeolitic imidazolate framework-8 grown in situ on CNTs (ZIF-8/CNTs). In the nanocomposite, the S-NCPs serve as an efficient host for immobilizing polysulfides through physical adsorption and chemical bonding, while the interleaved CNT networks offer an efficient charge transport environment. Moreover, the S-NCP/CNT composite with great features of a large specific surface area, high pore volume, and short electronic/ion diffusion depth not only demonstrates a high trapping capacity for soluble lithium polysulfides but also offers an efficient charge/mass transport environment, and an effective buffering of volume changes during charge and discharge. As a result, the Li-S batteries based on a S/S-NCP/CNT cathode deliver a high initial capacity of 1213.8 mAh g-1 at a current rate of 0.2 C and a substantial capacity of 1114.2 mAh g-1 after 100 cycles, corresponding to a high-capacity retention of 91.7%. This approach provides a practical research direction for the design of MOF-derived carbon materials in the application of high-performance Li-S batteries.