Manufacturing Water-Based Low-Tortuosity Electrodes for Fast-Charge through Pattern Integrated Stamping

Achieving high energy density and fast charging of lithium-ion batteries can accelerate the promotion of electric vehicles.However,the increased mass loading causes poor charge transfer,impedes the electrochemical reaction kinetics,and limits the battery charging rate.Herein,this work demonstrated a novel pattern integrated stamping process for creating channels in the electrode,which benefits ion transport and increases the rate performance of the electrode.Meanwhile,the pressure applied during the stamping process improved the contact between electrode and current collector and also enhanced the mechanical stability of the electrode.Compared to the conventional bar-coated electrode with the same thickness of 155μm(delivered a discharge capacity of 16 mAh g^(−1) at the rate of 3 C),the stamped low-tortuosity LiFePO_(4) electrode delivered 101 mAh g^(−1) capacity.Additionally,water was employed as a solvent in this study.Owing to its eco-friendliness,high scalability,and minimal waste generation,this novel stamping technique inspire a new method for the industrial-level efficient roll to roll fabrication of fast-charge electrodes.

Unraveling the Fundamental Mechanism of Interface Conductive Network Influence on the Fast‑Charging Performance of SiO‑Based Anode for Lithium‑Ion Batteries

Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.

Design aspects of electrolytes for fast charge of Li-ion batteries

The electrolytes of Li-ion batteries consist mainly of a LiPF6 salt dissolved in a carbonate-based solvent mixture.Such electrolytes cannot support fast charge without detrimental impacts on performance and lifetime.Fast charge aggravates parasitic reactions of the electrolyte solvents and structural degradation of the lithium layered transition metal oxide cathode materials.This leads to not only the depletion of electrolyte solvents but also the loss of cyclable Li+ions,accompanied by impedance growth and volumetric swelling of the battery.In this perspective,the design aspects of the electrolytes for fast charge of Li-ion batteries are discussed and proposed.

Towards extreme fast charging of 4.6 V LiCoO_(2) via mitigating high-voltage kinetic hindrance

High-voltage LiCoO_(2)(LCO) is an attractive cathode for ultra-high energy density lithium-ion batteries(LIBs) in the 3 C markets.However,the sluggish lithium-ion diffusion at high voltage significantly hampers its rate capability.Herein,combining experiments with density functional theory(DFT) calculations,we demonstrate that the kinetic limitations can be mitigated by a facial Mg^(2+)+Gd^(3+)co-doping method.The as-prepared LCO shows significantly enhanced Li-ion diffusion mobility at high voltage,making more homogenous Li-ion de/intercalation at a high-rate charge/discharge process.The homogeneity enables the structural stability of LCO at a high-rate current density,inhibiting stress accumulation and irreversible phase transition.When used in combination with a Li metal anode,the doped LCO shows an extreme fast charging(XFC) capability,with a superior high capacity of 193.1 mAh g^(-1)even at the current density of 20 C and high-rate capacity retention of 91.3% after 100 cycles at 5 C.This work provides a new insight to prepare XFC high-voltage LCO cathode materials.

Hard-carbon hybrid Li-ion/metal anode enabled by preferred mesoporous uniform lithium growth mechanism

To achieve high energy density in lithium batteries,the construction of lithium-ion/metal hybrid anodes is a promising strategy.In particular,because of the anisotropy of graphite,hybrid anode formed by graphite/Li metal has low transport kinetics and is easy to causes the growth of lithium dendrites and accumulation of dead Li,which seriously affects the cycle life of batteries and even causes safety problems.Here,by comparing graphite with two types of hard carbon,it was found that hybrid anode formed by hard carbon and lithium metal,possessing more disordered mesoporous structure and lithophilic groups,presents better performance.Results indicate that the mesoporous structure provides abundant active site and storage space for dead lithium.With the synergistic effect of this structure and lithophilic functional groups(–COOH),the reversibility of hard carbon/lithium metal hybrid anode is maintained,promoting uniform deposition of lithium metal and alleviating formation of lithium dendrites.The hybrid anode maintains a 99.5%Coulombic efficiency(CE)after 260 cycles at a specific capacity of 500 m Ah/g.This work provides new insights into the hybrid anodes formed by carbon-based materials and lithium metal with high specific energy and fast charging ability.

High Power Density EV Integrated Fast Battery Chargers Based on the General Torque Cancelation Law for Three-Phase Motors

Integrated battery chargers are highly effective for saving costs and improving the power density of on-board chargers in electric vehicles (EVs), However, achieving torque elimination of the commonly used three-phase (3p) motors during the fast-charging process is challenging. In this paper, the general torque cancelation law applied in 3p permanent magnet synchronous motors (PMSMs) and induction motors (IMs) is derived to design high power density integrated fast battery chargers. Two novel integrated systems with fast-charging and vehicle-to-grid (V2G) capabilities are proposed based on this law. The main advantages of the proposed systems are: (1) Two filter inductors are constituted by the stator windings while charging, and only one external inductor and several contactors are supplemented to the motor-drive circuit. Therefore, the proposed integrated systems possess high power density;(2) The 3p open-winding (OW) motor is employed, with no need to modify the propulsion system or redesign the interior structure of the motor;(3) Employing an individual controller for each phase of the inner current loop control, the proposed systems realize unity power factors and low current harmonics in the fast-charging and V2G mode. Simulation and experimental results verify the feasibility of the proposed topologies and control strategies.

ZnO Additive Boosts Charging Speed and Cycling Stability of Electrolytic Zn–Mn Batteries

Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability.

Energy-storage configuration for EV fast charging stations considering characteristics of charging load and wind-power fluctuation

Fast charging stations play an important role in the use of electric vehicles(EV)and significantly affect the distribution network owing to the fluctuation of their power.For exploiting the rapid adjustment feature of the energy-storage system(ESS),a configuration method of the ESS for EV fast charging stations is proposed in this paper,which considers the fluctuation of the wind power as well as the characteristics of the charging load.The configuration of the ESS can not only mitigate the effects of fast charging stations on the connected distribution network but also improve its economic efficiency.First,the scenario method is adopted to model the wind power in the distribution network,and according to the characteristics of the EV and the driving probability,the charging demand of each station is calculated.Then,considering factors such as the investment cost,maintenance cost,discharging benefit,and wind curtailment cost,the ESS configuration model of the distribution network is set up,which takes the optimal total costs of the ESS for EV fast charging stations within its lifecycle as an objective.Finally,General Algebraic Modelling System(GAMS)is used to linearize and solve the proposed model.A simulation on an improved IEEE-69 bus system verifies the feasibility and economic efficiency of the proposed model.

Tailoring Nitrogen Terminals on MXene Enables Fast Charging and Stable Cycling Na-Ion Batteries at Low Temperature

Sodium-ion batteries stand a chance of enabling fast charging ability and long lifespan while operating at low temperature(low-T).However,sluggish kinetics and aggravated dendrites present two major challenges for anodes to achieve the goal at low-T.Herein,we propose an interlayer confined strategy for tailoring nitrogen terminals on Ti_(3)C_(2) MXene(Ti_(3)C_(2)-N_(funct)) to address these issues.The introduction of nitrogen terminals endows Ti_(3)C_(2)-N_(funct) with large interlayer space and charge redistribution,improved conductivity and sufficient adsorption sites for Na^(+),which improves the possibility of Ti_(3)C_(2) for accommodating more Na atoms,further enhancing the Na^(+) storage capability of Ti_(3)C_(2).As revealed,Ti_(3)C_(2)-N_(funct) not only possesses a lower Na-ion diffusion energy barrier and charge trans-fer activation energy,but also exhibits Na^(+)-solvent co-intercalation behavior to circumvent a high de-solvation energy barrier at low-T.Besides,the solid electrolyte interface dominated by inorganic com-pounds is more beneficial for the Na^(+)transfer at the electrode/electrolyte interface.Compared with of the unmodified sample,Ti_(3)C_(2)-Nfunct exhibits a twofold capacity(201 mAh g^(-1)),fast-charging ability(18 min at 80% capacity retention),and great superiority in cycle life(80.9%@5000 cycles)at -25℃.When coupling with Na_(3)V_(2)(PO_(4))_(2)F_(3) cathode,the Ti_(3)C_(2)-N_(funct)//NVPF exhibits high energy density and cycle stability at -25℃.

An ultra-fast charging strategy for lithium-ion battery at low temperature without lithium plating

Conventional charging methods for lithium-ion battery(LIB)are challenged with vital problems at low temperatures:risk of lithium(Li)plating and low charging speed.This study proposes a fast-charging strategy without Li plating to achieve high-rate charging at low temperatures with bidirectional chargers.The strategy combines the pulsed-heating method and the optimal charging method via precise control of the battery states.A thermo-electric coupled model is developed based on the pseudo-twodimensional(P2D)electrochemical model to derive charging performances.Two current maps of pulsed heating and charging are generated to realize real-time control.Therefore,our proposed strategy achieves a 3 C equivalent rate at 0℃ and 1.5 C at-10℃ without Li plating,which is 10–30 times faster than the traditional methods.The entropy method is employed to balance the charging speed and the energy efficiency,and the charging performance is further enhanced.For practical application,the power limitation of the charger is considered,and a 2.4 C equivalent rate is achieved at 0℃ with a 250 kW maximum power output.This novel strategy significantly expands LIB usage boundary,and increases charging speed and battery safety.

Two-in-one shell configuration for bimetal selenides toward fast sodium storage within broadened voltage windows

The shell structure design has been recognized as a highly efficient strategy to buffer the severe volume expansion and consecutive pulverization of conversion-type anodes.Nevertheless,construction of a functional shell with a stabilized structure that meets the demands of both high electronic conductivity and feasible pathways for Na^(+)ions has been a challenge so far.Herein,we design a two-in-one shell configuration for bimetal selenides to achieve fast sodium storage within broadened voltage windows.The hybridized shell,which benefits from the combination of titanium dioxide quantum dots and amorphous carbon,can not only effectively buffer the strain and maintain structural integrity but also allow facile and reversible transport of electrons and Na^(+)uptake for electrode materials during sodiation/desodiation processes,resulting in increased reaction kinetics and diffusion of sodium ions,conferring many benefits to the functionality of conversion-type electrode materials.As a representative material,Ni-CoSe_(2) with such structural engineering shows a reversible capacity of 515 mAh g^(−1)at 0.1 A g^(−1)and a stable capacity of 416 mAh g^(−1)even at 6.4 A g^(−1);more than 80%of the capacity at 0.1 A g^(−1)could be preserved,so that this strategy holds great promise for designing fast-charging conversion-type anodes in the future.

Electrolyte inhomogeneity induced lithium plating in fast charging lithium-ion batteries

Fast charging capability of lithium-ion batteries is in urgent need for widespread economic success of electric vehicles. However, the application of the fast charging technology often leads to the inevitable lithium plating on the graphite anode, which is one of the main culprits that endanger battery safety and shorten battery lifespan. The in-depth understanding of the initiation of lithium metal nucleation and the following plating behavior is a key to the development of fast charging cells. Herein, we investigate the overlooked effect of the non-uniform distribution of electrolyte on lithium plating during fast charging. Prior lithium plating occurs on the saturated lithium-graphite compounds in the anode region with sufficient electrolyte since the lithium-ion transport is blocked in the anode region lacking electrolyte. The uniform distribution of electrolyte is crucial for the construction of safe lithium-ion batteries especially in fast charging scenarios.

Effects of long-term fast charging on a layered cathode for lithium-ion batteries

Fast charging, which aims to shorten recharge times to 10–15 min, is crucial for electric vehicles(EVs),but battery capacity usually decays rapidly if batteries are charged under such severe conditions.Revealing the failure mechanism is a prerequisite to improving the charging performance of lithium(Li)-ion batteries. Previous studies have focused less on cathode materials while also mostly focusing on their early changes. Thus, the cumulative effect of long-term fast charging on cathode materials has not been fully studied. Here, we study the changes in a layered cathode material during 1000 cycles of 6 C charging based on 1.6 Ah LiCoO_(2)/graphite pouch cells. Postmortem analysis reveals that the surface structure, charge transfer resistance and Li-ion diffusion coefficient of the cathode degenerate during repeated fast charging, causing a large increase in polarization. This polarization-induced poor utilization of the Li inventory is an important reason for the rapid capacity fading of batteries. These findings deepen the understanding of the aging mechanism for cells undergoing fast charging and can be used as benchmarks for the future development of high-capacity, fast-charging layered cathode materials.

Atomic Interface Catalytically Synthesizing SnP/CoP Hetero-Nanocrystals within Dual-Carbon Hybrids for Ultrafast Lithium-Ion Batteries

Tin phosphides are attractive anode materials for ultrafast lithium-ion batteries(LIBs)because of their ultrahigh Li-ion diffusion capability and large theoretical-specific capacity.However,difficulties in synthesis and large size enabling electrochemical irreversibility impede their applications.Herein,an in situ catalytic phosphorization strategy is developed to synthesize SnP/CoP hetero-nanocrystals within reduced graphene oxide(rGO)-coated carbon frameworks,in which the SnP relative formation energy is significantly decreased according to density functional theory(DFT)calculations.The optimized hybrids exhibit ultrafast charge/discharge capability(260 mA·h·g^(-1)at 50 A·g^(-1))without capacity fading(645 mA·h·g^(-1)at 2 A·g^(-1))through 1500 cycles.The lithiation/delithiation mechanism is disclosed,showing that the 4.0 nm sized SnP/CoP nanocrystals possess a very high reversibility and that the previously formed metallic Co of CoP at a relatively high potential accelerates the subsequent reaction kinetics of SnP,hence endowing them with ultrafast charge/discharge capability,which is further verified by the relative dynamic current density distributions according to the finite element analysis.

Modeling of fast charging station equipped with energy storage

The popularization of EVs(electric vehicles) has brought an increasingly heavy burden to the development of charging facilities. To meet the demand of rapid energy supply during the driving period, it is necessary to establish a fast charging station in public area. However, EVs arrive at the charging station randomly and connect to the distribution network for fast charging, it causes the grid power to fluctuate greatly and the peak-valley loads to alternate frequently, which is harmful to the stability of distribution network. In order to reduce the power fluctuation of random charging, the energy storage is used for fast charging stations. The queuing model is determined to demonstrate the load characteristics of fast charging station, and the state space of fast charging station system is described by Markov chain. After that the power of grid and energy storage is quantified as the number of charging pile, and each type of power is configured rationally to establish the random charging model of energy storage fast charging station. Finally, the economic benefit is analyzed according to the queuing theory to verify the feasibility of the model.

Scalable Synthesis of LiF-rich 3D Architected Li Metal Anode via Direct Lithium-Fluoropolymer Pyrolysis to Enable Fast Li Cycling

Lithium metal anode holds an important position in fast-charging batteries.But lithium dendrite issues tend to exacerbate at high currents.Li F can be considered as an effective way to improve the Li metal surface electrochemical stability to achieve high power and high energy.However,most of reported work are relying on in situ formation of a 2D Li F on Li metal in liquid electrolyte,which limits the scalability and plated Li quantity.Here,we address this challenge and report a scalable synthesis of Li F-rich 3D architected Li metal anode via a direct pyrolysis of molten lithium and fluoropolymer to enable fast Li charging with high current density(20 mA cm-2)and high areal capacity(20 m Ah cm-2).The 3D structure is synthesized by the pyrolysis of fluoropolymer with Li metal and results show high similarity to the pristine electrolyte-derived solid-electrolyte-interphase(SEI).This concept using pyrolysis of fluoropolymer with Li-containing active materials could be also extended to modify Li metal oxide cathode(e.g.,Li Ni0.5Mn1.5O4)for mixed conductive interphase and engineer Li solid ion conductors(e.g.,Li garnet-type oxides)for interface stabilization andframework design.

The Puzzles in Fast Charging of Li-Ion Batteries

Fast charging of Li-ion cells faces two aspects of challenges,1)accelerated capacity fade and 2)inferior charging capability.It is commonly believed that the former is due to Li plating and its resultant reactions with electrolyte at the graphite anode,which results in a loss in the inventory of Li+ions and an increase in the cell’s impedance.While the latter is ascribed to the high voltage polarization in relation to the slow transport of Li+ions between two electrodes.However,there are many other hidden facts that essentially affect the fast charging performances of Li-ion cells.This commentary intends,from the view of materials,to uncover these hidden factors,including failure of the solid electrolyte interphase and exfoliation of the graphite structure at the anode,structural degradation of the Ni-rich layered cathode materials,as well as the high solvation and desolvation activation energies of Li+ions in the electrolyte.Meanwhile,some solutions to the fast-charging problems of Li-ion cells are proposed based on the understanding of these hidden factors.

China drafts first standard on fast charging

In recent years,fast charging develops by leaps and bounds and growth rate is doubling.It is expected to be the biggest growth point in the market of consumer electronic accessories in the future.However,different fast charging standards made by enterprises have troubled consumers.To this end,the first fast charging standard draft in China even in the world--"technical requirements and testing methods for mobile terminal fast charging technology"has been completed after three

Overview of multi-stage charging strategies for Li-ion batteries

To reduce the carbon footprint in the transportation sector and improve overall vehicle efficiency,a large number of electric vehicles are being manufactured.This is due to the fact that environmental concerns and the depletion of fossil fuels have become significant global problems.Lithium-ion batteries(LIBs)have been distinguished themselves from alternative energy storage technologies for electric vehicles(EVs) due to superior qualities like high energy and power density,extended cycle life,and low maintenance cost to a competitive price.However,there are still certain challenges to be solved,like EV fast charging,longer lifetime,and reduced weight.For fast charging,the multi-stage constant current(MSCC) charging technique is an emerging solution to improve charging efficiency,reduce temperature rise during charging,increase charging/discharging capacities,shorten charging time,and extend the cycle life.However,there are large variations in the implementation of the number of stages,stage transition criterion,and C-rate selection for each stage.This paper provides a review of these problems by compiling information from the literature.An overview of the impact of different design parameters(number of stages,stage transition,and C-rate) that the MSCC charging techniques have had on the LIB performance and cycle life is described in detail and analyzed.The impact of design parameters on lifetime,charging efficiency,charging and discharging capacity,charging speed,and rising temperature during charging is presented,and this review provides guidelines for designing advanced fast charging strategies and determining future research gaps.

Microporous Cyclodextrin Film with Funnel-type Channel Polymerized on Electrospun Cellulose Acetate Membrane as Separators for Strong Trapping Polysulfides and Boosting Charging in Lithium-Sulfur Batteries

The“shuttle effect”of polysulfides hampers the commercialization of lithium-sulfur(Li-S)batteries.Here,a thin molecular sieve film was decorated on the surface of an electrospun cellulose acetate(CA)membrane derived from recycled cigarette filters,where the truncated cone structureβ-cyclodextrin(β-CD)was selected as the building block to physically block and chemically trap polysulfides while simultaneously dramatically speeding up ion transport.Furthermore,on theβ-CD free side of the separator facing the cathode,graphite carbon(C)was sputtered as an upper current collector,which barely increases the thickness.These benefits result in an initial discharge performance of 1378.24 mAh g^(−1) and long-term cycling stability of 863.78 mAh g^(−1) after 1000 cycles at 0.2 C for the battery with theβ-CD/CA/C separator,which is more than three times that of the PP separator after 500 cycles.Surprisingly,the funnel-type channel ofβ-CD generates a differential ionic fluid pressure on both sides,speeding up ion transport by up to 69%,and a 65.3%faster charging rate of 9484 mA g^(−1) was achieved.The“funnel effect”of a separator is regarded as a novel and high-efficiency solution for fast charging of Li-S and other lithium secondary batteries.