Lithium-ion Battery Technology Research Articles

Machine learning enhanced control co-design optimization of an immersion cooled battery thermal management system

The development of lithium-ion battery technology has ensured that battery thermal management systems are an essential component of the battery pack for next-generation energy storage systems. Using dielectric immersion cooling, researchers have demonstrated the ability to attain high heat transfer rates due to the direct contact between cells and the coolant. However, feedback control has not been widely applied to immersion cooling schemes. Furthermore, current research has not considered battery pack plant design when optimizing feedback control. Uncertainties are inherent in the cooling equipment, resulting in temperature and flow rate fluctuations. Hence, it is crucial to systematically consider these uncertainties during cooling system design to improve the performance and reliability of the battery pack. To fill this gap, we established a reliability-based control co-design optimization framework using machine learning for immersion cooled battery packs. We first developed an experimental setup for 21700 battery immersion cooling, and the experiment data were used to build a high-fidelity multiphysics finite element model. The model can precisely represent the electrical and thermal profile of the battery. We then developed surrogate models based on the finite element simulations in order to reduce computational cost. The reliability-based control co-design optimization was employed to find the best plant and control design for the cooling system, in which an outer optimization loop minimized the cooling system cost while an inner loop ensured battery pack reliability. Finally, an optimal cooling system design was obtained and validated, which showed a 90% saving in cooling system energy consumption.

Machine learning enhanced control co-design optimization of an immersion cooled battery thermal management system

The development of lithium-ion battery technology has ensured that battery thermal management systems are an essential component of the battery pack for next-generation energy storage systems. Using dielectric immersion cooling, researchers have demonstrated the ability to attain high heat transfer rates due to the direct contact between cells and the coolant. However, feedback control has not been widely applied to immersion cooling schemes. Furthermore, current research has not considered battery pack plant design when optimizing feedback control. Uncertainties are inherent in the cooling equipment, resulting in temperature and flow rate fluctuations. Hence, it is crucial to systematically consider these uncertainties during cooling system design to improve the performance and reliability of the battery pack. To fill this gap, we established a reliability-based control co-design optimization framework using machine learning for immersion cooled battery packs. We first developed an experimental setup for 21700 battery immersion cooling, and the experiment data were used to build a high-fidelity multiphysics finite element model. The model can precisely represent the electrical and thermal profile of the battery. We then developed surrogate models based on the finite element simulations in order to reduce computational cost. The reliability-based control co-design optimization was employed to find the best plant and control design for the cooling system, in which an outer optimization loop minimized the cooling system cost while an inner loop ensured battery pack reliability. Finally, an optimal cooling system design was obtained and validated, which showed a 90% saving in cooling system energy consumption.

Comprehensive Understanding of Elemental Doping and Substitution of Ni‐Rich Cathode Materials for Lithium‐Ion Batteries via In Situ Operando Analyses

This review explores the challenges and advancements in the development of high‐energy lithium‐ion batteries (LIBs), particularly focusing on the electrochemical and structural stability of Ni‐rich cathode materials. Despite their potential to increase the energy density of LIBs, these cathode materials encounter issues such as irreversible phase transitions and structural degradation during cycling, which ultimately affect their electrochemical performance. Elemental doping/substitution has emerged as promising strategies to address these challenges. However, the precise mechanisms underlying their performance enhancement remain unclear. The objective is to elucidate the complex reaction mechanisms triggered by doping and substitution in Ni‐rich cathode materials by employing in situ operando analyses to uncover their effects on electrochemical behavior and structural integrity during cycling. This comprehensive investigation aims to clarify the roles of elemental dopants or substituents in the crystal structures of Ni‐rich cathode materials, thereby offering valuable insights for the structural engineering of cathode materials in high‐energy LIBs. By elucidating these intricate mechanisms, this review provides a practical roadmap for future research and significantly contributes to LIB technology by guiding material design and optimization strategies in the development of advanced LIBs.

Halide solid-state electrolyte achieving high ionic conductivity by engineering nanocrystals

Lithium-ion battery (LIB) technologies utilize liquid electrolytes, which can cause safety issues due to electrolyte leakage, uncontrolled side reactions between the liquid electrolyte and electrode, dendrite formation, and flammability of the liquid components with air. These problems can be minimized using solid-state electrolytes (SSEs) containing the functionality of an electrolyte. Our research discovery meets the urgent requirement of developing rapid ionic conductive solid-state electrolytes for lithium metal battery applications, emphasizing safe operation and high energy density. The breakthrough lies in the functionalization and tunability of monoclinic doped Li3InCl6-based solid electrolytes to achieve desirable structural and high ionic conductivity (> 0.15 S cm−1). We report four formulations of solid-state electrolytes obtained using modified sol–gel synthesis and used to assemble symmetrical half cells for electrochemical impedance spectroscopic (EIS) analyses in the frequency ranging from 10–2 to 106 Hz under five different temperatures (15–55 °C). The EIS data of non-doped, F-, Ce-, and Mo-doped electrolytes showed R1 (solid-electrolyte) ranging from 0.05 to 0.10 Ohm and R2 (interfacial) resistance varying from 0.05 to 1.25 Ohm, resulting in superionic conductivity (0.15–0.45 S cm−1), equivalent to the commercially available liquid electrolyte and evidenced two magnitudes increase compared to the published data.Graphical abstract

Enhanced mechanical and surface chemical stability in cobalt-free, high-nickel cathode materials for lithium-ion batteries

Cobalt-free, high-nickel cathode materials are essential for the sustainable evolution of energy storage technologies, reducing the dependence on resources with significant environmental and social implications and simultaneously improving the efficiency and cost effectiveness of batteries. This paper introduces a cobalt-free, high-nickel cathode material called 0.01B-LiNi0.98Mg0.01Zr0.01O2 (NMZB) developed using a novel blend of elements to enhance mechanical and surface chemical stability. Detailed evaluations confirmed the successful integration of Mg, Zr, and B into the particles, with Mg and Zr primarily located within the particle interior and B predominantly on the surface. This unique elemental configuration significantly improves the stability of the bulk phase and surface structure of the material. In addition, the refinement of primary particles within NMZB further enhances its mechanical stability. As a result, NMZB exhibits exceptional electrochemical stability, achieving 90.5 % capacity retention after 200 cycles at a 1C rate. This compositional strategy incorporates a high nickel content into layered materials while eliminating cobalt, which is crucial for advancing the development of cost effective and high-performance lithium-ion battery technology.

Optimization of LiNiCoMnO2 Cathode Material Synthesis Using Polyvinyl Alcohol Solution Method for Improved Lithium-Ion Batteries.

The growing need for lithium-ion batteries, fueled by the widespread use of electric vehicles (EVs) and portable electronic devices, requires high energy density and safety. The cathode material Li1-x(NiyCozMn1-y-z)O2 (NCM) shows promise, but attaining high efficiency necessitates optimization of both composition and manufacturing methods. Polycrystalline LiNiCoMnO2 powders were synthesized and assessed in this investigation using a polyvinyl alcohol (PVA) solution method. The study examined different synthesis conditions, such as the PVA to metal ions ratio and the molecular weight of PVA, to assess their influence on powder characteristics. Electrochemical analysis indicated that cathode materials synthesized with a relatively high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10-9 cm2/s. Moreover, decreasing the PVA content, irrespective of its molecular weight, led to the production of powders with reduced surface areas and increased pore sizes. The adjustments of PVA during synthesis resulted in pre-sintering observed during the synthesis process, which had an impact on the long-term stability of batteries. The electrodes produced from the synthesized powders had a positive impact on the insertion and extraction of Li+ ions, thereby improving the electrochemical performance of the batteries. This study reveals that cathode materials synthesized with a high quantity of PVA with a molecular weight of 98,000 exhibited the highest discharge capacity of 170.34 mAh/g and a high lithium-ion diffusion coefficient of 1.19 × 10-9 cm2/s. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials to enhance the electrochemical properties of NCM cathode materials, contributing to the advancement of lithium-ion battery technology. The findings underscore the significance of optimizing methods for synthesizing PVA-based materials and their influence on the electrochemical properties of NCM cathode materials. This contributes to the continuous progress in lithium-ion battery technology.

Enhanced electrochemical performance of a LiFePO4 cathode with an environmentally friendly pectin/polyethylene glycol binder

The advancement of lithium-ion battery technology relies on the development of materials that not only improve performance but also align with environmental sustainability. This work presents a novel water-based pectin-PEG binder for LiFePO4 cathodes that combines eco-friendliness with electrochemical innovation. The binder material is made by mixing pectin, a flexible natural substance, with polyethylene glycol through a radical copolymerization process. This combination gives the binder both flexibility and a boost in electrical performance. Our experimental results demonstrate that LFP cathodes with this binder have an intriguing self-healing ability in comparison with the conventional PVDF binder, enhanced charge-discharge capacities, improved cycling stability, and higher ionic conductivity. Specifically, electrodes utilizing the pectin-PEG binder exhibit an impressive retention of discharge capacity. They maintain roughly 150 mAh g−1 after 500 cycles at 1C with 99% retention, and about 141 mAh g−1 with 97% retention at 3C. Cyclic voltammetry (CV) confirms that the PP binder maintains its ionic diffusion properties at high sweep rates, whereas galvanostatic intermittent titration technique reveals a much higher lithium ion diffusion coefficient (DLi+) within the operational voltage range of the LFP-PP250 electrodes. These findings establish an attractive direction for the development of electrodes for high-energy density, sustainable lithium-ion batteries.

Innovations and strategies for optimizing lithium-ion battery performance: From material advancements to system management

This paper explores the multifaceted advancements in lithium-ion battery (LIB) technology, focusing on material innovations and engineering strategies aimed at optimizing performance, safety, and efficiency. We delve into the development of advanced cathode materials like lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP), highlighting their contributions to enhancing energy density and safety. The investigation extends to silicon-based anode materials, underscoring their potential to significantly increase energy storage capacity despite challenges related to volume expansion. Furthermore, we discuss electrolyte optimization techniques that promise to improve battery safety through the use of non-flammable ionic liquids and solid-state electrolytes. Engineering strategies, including microstructure design of electrodes and thermal management systems, are analyzed for their role in improving electrochemical performance and extending battery lifespan. Smart battery management systems (BMS) are also examined for their ability to optimize battery usage through real-time monitoring and predictive analytics. Through a comprehensive review and quantitative analysis, this study presents a cohesive overview of current trends and future directions in LIB technology.

Doping Effects on Ternary Cathode Materials for Lithium-Ion Batteries: A Review.

The ongoing advancements in lithium-ion battery technology are pivotal in propelling the performance of modern electronic devices and electric vehicles. Amongst various components, the cathode material significantly influences the battery performance, such as the specific capacity, capacity retention and the rate performance. Ternary cathode materials, composed of nickel, manganese, and cobalt (NCM), offer a balanced combination of these traits. Recent developments focus on elemental doping, which involves substituting a fraction of NCM constituent ions with alternative cations such as aluminum, titanium, or magnesium. This strategic substitution aims to enhance structural stability, increase capacity retention, and improve resistance to thermal runaway. Doped ternary materials have shown promising results, with improvements in cycle life and operational safety. However, the quest for optimal doping elements and concentrations persists to maximize performance while minimizing cost and environmental impact, ensuring the progression towards high-energy-density, durable, and safe battery technologies.

Investigating the expansion behavior of silicon nanoparticles and the effects of electrolyte composition using a graphene liquid cell

Understanding the volume expansion behavior of Si anodes and their interaction with electrolyte environments is crucial for developing high-performance lithium-ion batteries (LIBs). This study utilizes a graphene liquid cell for in situ imaging to systematically investigate the volume expansion and etching behavior of Si anode nanoparticles in different electrolyte environments. Comparative experiments on Si@C core-shell nanoparticles assess their volume expansion dynamics. The findings reveal significant variation in the expansion rate of nano Si depending on the electrolyte environment, with chemical etching observed under specific conditions. Conversely, Si@C core-shell structures show mitigated expansion due to the confinement effect of the carbon matrix. Battery performance experiments validate these results, demonstrating the excellent cycling stability of Si@C anodes. Various coating agents are explored to optimize Si@C structures, with dopamine thin layer coating exhibiting the best cycling stability. This study offers fundamental insights into Si anode expansion, electrolyte effects, and carbon coating impacts, advancing LIB technology.

Modelling Li-V2O5 Batteries Using Galvanostatic Intermittent Titration Technique and Electrochemical Impedance Spectroscopy: Towards Final Applications

Given the relevance of lithium and post-lithium batteries as electrochemical energy storage systems, the peculiar crystalline structure of V2O5 and its doping capacity play key roles in lithium-ion battery technology. To integrate them in high-efficiency modules, systematic methodologies are required to estimate the state of charge in a reliable way and predict the Li-V2O5 battery’s performance according to their electrochemical phenomena, including two plateaus in the galvanostatic cycling curves and the dynamic behavior governed by the energy demand. Most state of charge estimation and battery modeling procedures are focused on conventional Li-batteries that show a unique plateau. In this work, we propose a systematic methodology based on the galvanostatic intermittent titration technique and electrochemical impedance spectroscopy to study battery performance in the time and frequency domains, respectively. The proposed methodology, with a time–frequency correlation, promotes a deeper understanding of the electrochemical phenomena and general behavior of Li-V2O5 batteries, allowing for its subsequent extrapolation to more complex and higher-capacity lithium and post-lithium batteries used in high-power applications with a minimum error.

Dry Electrode Processing Technology and Binders.

As a popular energy storage equipment, lithium-ion batteries (LIBs) have many advantages, such as high energy density and long cycle life. At this stage, with the increasing demand for energy storage materials, the industrialization of batteries is facing new challenges such as enhancing efficiency, reducing energy consumption, and improving battery performance. In particular, the challenges mentioned above are particularly critical in advanced next-generation battery manufacturing. For batteries, the electrode processing process plays a crucial role in advancing lithium-ion battery technology and has a significant impact on battery energy density, manufacturing cost, and yield. Dry electrode technology is an emerging technology that has attracted extensive attention from both academia and the manufacturing industry due to its unique advantages and compatibility. This paper provides a detailed introduction to the development status and application examples of various dry electrode technologies. It discusses the latest advancements in commonly used binders for different dry processes and offers insights into future electrode manufacturing.

Advancing Smart Lithium-Ion Batteries: A Review on Multi-Physical Sensing Technologies for Lithium-Ion Batteries

Traditional battery management systems (BMS) encounter significant challenges, including low precision in predicting battery states and complexities in managing batteries, primarily due to the scarcity of collected signals. The advancement towards a “smart battery”, equipped with diverse sensor types, promises to mitigate these issues. This review highlights the latest developments in smart sensing technologies for batteries, encompassing electrical, thermal, mechanical, acoustic, and gas sensors. Specifically, we address how these different signals are perceived and how these varied signals could enhance our comprehension of battery aging, failure, and thermal runaway mechanisms, contributing to the creation of BMS that are safer and more reliable. Moreover, we analyze the limitations and challenges faced by different sensor applications and discuss the advantages and disadvantages of each sensing technology. Conclusively, we present a perspective on overcoming future hurdles in smart battery development, focusing on appropriate sensor design, optimized integration processes, efficient signal transmission, and advanced management systems.

Construction of plum-branch-like CoSe2@N-Doped carbon/carbon fiber with dual protective mechanisms for enhanced lithium storage

Cobalt selenide (CoSe2) emerges as a highly promising anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity and cost-effectiveness. Despite these merits, its practical utilization faces challenges stemming from substantial volume fluctuations and limited electronic conductivity. To tackle these issues, a plum-branch-like structure of CoSe2@N-doped carbon that embedded in one-dimensional N-doped carbon fibers (CoSe2@NC/CFs), is successfully synthesized through an in-situ confinement method. Well-defined CoSe2@NC nanoparticles, featuring diameters between 20∼30 ​nm, are uniformly dispersed on both the inner and outer surfaces of the carbon fibers. The distinctive architecture of CoSe2@NC/CFs ensures an increased number of active sites, elevated electronic conductivity, alleviated volume expansion, and accelerated reaction kinetics. Consequently, the CoSe2@NC/CFs exhibits remarkable cycling performance and exceptional rate capability. Operating at a current density of 1000 ​mA ​g−1, the CoSe2@NC/CFs anode sustains a capacity of 664 ​mA ​h ​g−1 with no obvious capacity decay over 500 cycles. Even at a high current density of 5000 ​mA ​g−1, it maintains a capacity of 445 ​mA ​h g−1 with a mere 0.02 ​% capacity decay per cycle. This study introduces a novel approach to anode material design, showcasing significant advancements in lithium-ion battery technology.

Polyester-enhanced poly (cyclic carbonate-fluoride)-based polymer electrolyte for stable circulating solid lithium batteries

Polymer solid-state electrolytes have become one of the promising materials for constructing solid-state lithium batteries due to their excellent processability and good compatibility with electrode interfaces. However, their limited electrochemical performance and mechanical strength have hindered their widespread application. Through the adoption of an in-situ thermal curing method, we successfully prepared a poly(carbonate-fluoride) solid-state electrolyte, utilizing a polyester separator with abundant polar groups as a reinforcing framework. The introduction of ionic liquid into the solid polymer electrolyte not only enhances the mobility of polymer chain segments to improve ionic conductivity but also, in synergy with trifluoromethyl, promotes lithium salt dissociation while restricting the migration of lithium salt anions. Additionally, their reaction with the lithium metal anode generates the LiF-rich SEI, regulating the deposition of lithium dendrites. The resulting 31VPIF/OZ exhibited outstanding ionic conductivity (3.58 × 10−4 S cm−1 at 25 °C), Li-ion migration number (0.52), and electrochemical window (5.4 V). Li | 31VPIF/OZ | Li battery cycled for 1000 h at 0.1 mA cm−2 without short-circuiting. Importantly, Li | | LiFePO4 battery demonstrated a high capacity retention rate of 91.5 % after 600 cycles at 0.5C (25 °C). Thus, through the synergistic interplay of polymer structure design and fillers, we have successfully achieved stable cycling in solid-state lithium batteries, providing robust support for their application in rechargeable lithium battery technology.

Innovative design of silicon-core mesoporous carbon composite for high performance anode material in advanced lithium-ion batteries

Silicon is widely recognized as an exceptionally auspicious anode material for lithium−ion batteries due to its remarkable specific capacity, suitable operational potential, and ecologically innocuous characteristics. This study presents a novel silicon@void@FC (fibrous carbon) composite anode material for lithium-ion batteries. Utilizing a one-step synthesis approach, the resulting hollow core–shell structure, combined with a mesoporous carbon shell, demonstrates exceptional electrochemical performance. The Si@Void@FC electrode exhibits remarkable cycle stability and rate performance, maintaining structural integrity over 500 cycles without observable degradation. The outer carbon shell acts as a protective layer and accommodates silicon volume expansion during cycling, preventing excessive contact with the electrolyte. The rich mesoporous structure facilitates efficient lithium-ion diffusion, enhancing lithiation and delithiation processes. The simplified one-step synthesis method further streamlines the preparation process, eliminating the need for complete silica template formation. This innovative Si@Void@FC composite material holds promise for advancing lithium-ion battery technology, addressing challenges associated with silicon-based anode materials, and offering insights into the design and synthesis of high-performance energy storage materials.

ANALISIS SPESIFIKASI TEKNIS SISTEM PENGEMUDIAN ELEKTRIK PADA KENDARAAN LISTRIK BERBASIS BATERAI KOMERSIAL POPULER

The increase in the number of motor vehicles in Indonesia has elevated the negative impact on the environment, both in terms of air pollution and global warming. According to the Ministry of Transportation (Kemhub), the number of motor vehicles in Indonesia reached 141.99 million units in 2021. The electrification of motor vehicles is one of the solutions to reduce emissions from the motor vehicle sector. This is supported by Presidential Regulation No. 55/2019 to stimulate the growth of the national battery-based electric vehicle (BEV) industry. This paper reviews battery-based electric vehicle (BEV) technology worldwide, especially four-wheeled vehicles with a high total population. The research was conducted through online surveys in 2023 using international data sources and the Association of Indonesian Automotive Industries (GAIKINDO), resulting in a database of 33 battery-based electric vehicles. From this database, it was found that the majority of electric cars purchased by the public are hatchback and sport utility vehicle (SUV) types. In terms of electric drive systems, the power capacity range of electric motors used by these vehicles is between 20 - 150 kW for hatchbacks and 100 - 406 kW for SUVs. The most commonly used electric motor type, constituting about 64%, is the Permanent Magnet Synchronous Motor (PMSM). About 70% of these vehicles use lithium-ion battery technology. The technical specifications of these popular electric cars are expected to assist stakeholders in quickly understanding the technical specifications of electric drive systems in battery-based electric vehicles, serving as a benchmark for designing electric cars suitable to meet domestic needs.

Fire Safety of Battery Electric Vehicles: Hazard Identification, Detection, and Mitigation

<div>Battery electric vehicles (EVs) bring significant benefits in reducing the carbon footprint of fossil fuels and new opportunities for adopting renewable energy. Because of their high-energy density and long cycle life, lithium-ion batteries (LIBs) are dominating the battery market, and the consumer demand for LIB-powered EVs is expected to continue to boom in the next decade. However, the chemistry used in LIBs is still vulnerable to experiencing thermal runaway, especially in harsh working conditions. Furthermore, as LIB technology moves to larger scales of power and energy, the safety issues turn out to be the most intolerable pain point of its application in EVs. Its failure could result in the release of toxic gases, fire, and even explosions, causing catastrophic damage to life and property. Vehicle fires are an often-overlooked part of the fire problem. Fire protection and EV safety fall into different disciplines. To bridge the gap between these two disciplines and summarize the state-of-the-art knowledge of fire safety issues of EVs, this review article will provide a comprehensive overview of their fire hazard identification, detection, and mitigation strategies. This article also highlights the failure mechanisms of LIBs in EVs, which establish the basis for understanding the LIB fire safety issues in EVs. The aim of this review article is to provide a general and basic understanding of the fire hazards of EVs from different scales to both engineers and researchers. This review article can also be used as educational material for the public and emergency responders to increase their awareness of the fire safety of modern EVs.</div>

Enhancing the cycling stability of commercial silicon nanoparticles by carbon coating and thin layered single-walled carbon nanotube webbing

Silicon-based anode materials are considered as the most attractive alternatives to traditional graphite anodes, thereby advancing the evolution of new-generation lithium-ion battery technology. However, the inadequate electrical conduction of silicon-based materials, along with severe volume expansion during charging and discharging processes, limits their further technological applications. Herein, a dual-layer carbon shell configuration is designed to efficiently alleviate the substantial volumetric expansion of silicon during cycles, while simultaneously improving the efficiency of both electron and lithium ions. The effectiveness of this layered buffering approach is credited to the networked structure of outer single-walled carbon nanotubes (SWCNTs) layer, which is firmly attached to the inner carbon shell's surface. The modified structure not only elevates the level of electrical conduction, but also significantly reduces the internal stress due to silicon's expansion. The developed Si@C@SWCNT electrode materials exhibit high capacity of 1267.3 mA h g−1 after 500 cycles at 1 A g−1, and sustains an elevated rate capacity of 863 mA h g−1 at 8 A g−1. This study highlights the enormous potential of Si@C@SWCNT composites for use in lithium-ion batteries and provides new perspectives for further exploration and utilization of silicon-carbon anodes.

Nanohoneycomb rGO foam as a promising anode material for unprecedented ultrahigh Li storage and excellent endurance at ampere current stability

Most rechargeable lithium-ion batteries (LIBs) exploit bulk carbon (e.g., graphite with low interlayer spacing of 0.335 nm) as an anode material despite its low theoretical capacity of 372 mAh/g because it has a high coulombic efficiency, good cycling performance, and low production costs. However, it is difficult to increase the specific capacity of graphite-based anodes without sacrificing these inherent advantages. In the present study, we developed reduced graphene oxide nanohoneycomb foam (H-rGO) as an anode material with higher surface area, porosity, and interlayer spacing for the rapid and efficient lithiation-delithiation of Li-ions. The combination of the hierarchical three-dimensional sponge-like mesoporous structure with highly efficient Li-ion conduction pathways and enlarge active surface area leads to a significantly improved specific capacity (1031 mAh/g at 0.1 A/g) and rapid charging with exceptional stability over 5,000 cycles. The H-rGO anode achieves an outstanding reversible capacity of ∼534 mAh/g over 2,500 cycles at 1.0 A/g, with a capacity retention of 87 and 84 % at high current densities of 10 and 20 A/g, respectively. Our approach is fully compatible with current LIBs technology and offer a simple and efficient strategy to significantly increase Li-storage capacity of under current graphite-based anode technology.