3D printing encouraging desired in-situ polypyrrole seed-polymerization for ultra-high energy density supercapacitors

The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly conductive polymer and a prospective pseudocapacitive materials for supercapacitors,yet the inferior cyclic stability and unpredictable polymerization patterns severely impede its real-world applicability.Here,for the first time,an innovative seed-induced in-situ polymerization assisted 3D printing strategy is proposed to fabricate PPy-reduced graphene oxide/poly(vinylidene difluoride-cohexafluoropropylene)(PVDF-HFP)(PPy-rGO/PH)electrodes with controllable polymerization behavior and exceptional areal mass loading.The preferred active sites uniformly pre-planted on the 3D-printed graphene substrates serve as reliable seeds to induce efficient polypyrrole deposition,achieving an impressive mass loading of 185.6 mg cm^(-2)(particularly 79.2 mg cm^(-2)for polypyrrole)and a superior areal capacitance of 25.2 F cm^(-2)at 2 mA cm^(-2)for a 12-layer electrode.In agreement with theses appealing features,an unprecedented areal energy density of 1.47 mW h cm^(-2)for a symmetrical device is registered,a rarely achieved value for other PPy/rGO-based supercapacitors.This work highlights a promising route to preparing high energy density energy storage modules for real-world applications.

High energy density in ultra-thick and flexible electrodes enabled by designed conductive agent/binder composite

Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.

"Win-Win"Scenario of High Energy Density and Long Cycling Life in a Novel Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)Cathode

The development of high-energy and long-lifespan NASICON-type cathode materials for sodium-ion batteries has always been a research hotspot but a daunting challenge.Although Na_(4)MnCr(PO_(4))_(3)has emerged as one of the most promising high-energy-density cathode materials owing to its three-electron reactions,it still suffers from serious structural distortion upon repetitive charge/discharge processes caused by the Jahn-Teller active Mn^(3+).Herein,the selective substitution of Cr by Zr in Na_(4)MnCr(PO_(4))_(3)was explored to enhance the structural stability,due to the pinning effect of Zr ions and the≈2.9-electron reactions,as-prepared Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C delivers a high capacity retention of 85.94%over 500 cycles at 5 C and an ultrahigh capacity of 156.4 mAh g^(-1)at 0.1 C,enabling the stable energy output as high as 555.2 Wh kg^(-1).Moreover,during the whole charge/discharge process,a small volume change of only 6.7%was verified by in situ X-ray diffraction,and the reversible reactions of Cr^(3+)/Cr^(4+),Mn^(3+)/Mn^(4+),and Mn^(2+)/Mn^(3+)redox couples were identified via ex situ X-ray photoelectron spectroscopy analyses.Galvanostatic intermittent titration technique tests and density functional theory calculations further demonstrated the fast reaction kinetics of the Na_(3.9)MnCr_(0.9)Zr_(0.1)(PO_(4))_(3)/C electrode.This work offers new opportunities for designing high-energy and high-stability NASICON cathodes by ion doping.

Particle Size Optimization of Thermochemical Salt Hydrates for High Energy Density Thermal Storage

Thermal energy storage(TES)solutions offer opportunities to reduce energy consumption,greenhouse gas emissions,and cost.Specifically,they can help reduce the peak load and address the intermittency of renewable energy sources by time shifting the load,which are critical toward zero energy buildings.Thermochemical materials(TCMs)as a class of TES undergo a solid-gas reversible chemical reaction with water vapor to store and release energy with high storage capacities(600 kWh m^(-3))and negligible self-discharge that makes them uniquely suited as compact,stand-alone units for daily or seasonal storage.However,TCMs suffer from instabilities at the material(salt particles)and reactor level(packed beds of salt),resulting in poor multi-cycle efficiency and high-levelized cost of storage.In this study,a model is developed to predict the pulverization limit or Rcrit of various salt hydrates during thermal cycling.This is critical as it provides design rules to make mechanically stable TCM composites as well as enables the use of more energy-efficient manufacturing process(solid-state mixing)to make the composites.The model is experimentally validated on multiple TCM salt hydrates with different water content,and effect of Rcrit on hydration and dehydration kinetics is also investigated.

Topological Structure-Modulated Collagen Carbon as Two-in-One Energy Storage Configuration toward Ultrahigh Power and Energy Density

Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).

A high-entropy-designed cathode with V^(5+)-V^(2+) multi-redox for high energy density sodium-ion batteries

Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON structure.But it still suffers from low electronic conductivity and inadequate energy density.Herein,a high-entropy modification strategy is realized by doping V^(3+)site with Ga^(3+)/Cr^(3+)/Al^(3+)/Fe^(3+)/In^(3+)simultaneously(i.e.Na_(3)V_(2-x)(GaCrAlFeIn)_x(PO_(4))_(3);x=0,0.04,0.06,and 0.08)to stimulate the V^(5+)■V^(2+)reversible multi-electron redox.Such configuration high-entropy can effectively suppress the structural collapse,enhance the redox reversibility in high working voltage(4.0 V),and optimize the electronic induced effect.The in-situ X-ray powder diffraction and in-situ electrochemical impedance spectroscopy tests efficaciously confirm the robust structu ral recovery and far lower polarization throughout an entire charge-discharge cycle during 1.6-4.3 V,respectively.Moreover,the density functional theory calculations clarify the stronger metallicity of high-entropy electrode than the bare that is derived from the more mobile free electrons surrounding the vicinity of Fermi level.By grace of high-entropy design and multi-electron transfer reactions,the optimal Na_(3)V_(1.7)(GaCrAlFeIn)_(0.06)(PO_(4))_(3)can exhibit perfect cycling/rate performances(90.97%@5000 cycles@30 C;112 mA h g^(-1)@10 C and 109 mA h g^(-1)@30 C,2.0-4.3 V).Furthermore,it can supply ultra-high185 mA h g^(-1)capacity with fa ntastic energy density(522 W h kg^(-1))in half-cells(1.4-4.3 V),and competitive capacity(121 mA h g^(-1))as well as energy density(402 W h kg^(-1))in full-cells(1.6-4.1 V),demonstrating enormous application potential for sodium-ion batteries.

A Number Theoretic Analysis of the Enthalpy, Enthalpy Energy Density, Thermodynamic Volume, and the Equation of State of a Modified White Hole, and the Implications to the Quantum Vacuum Spacetime, Matter Creation and the Planck Frequency

In this paper, we analyze the enthalpy, enthalpy energy density, thermodynamic volume, and the equation of state of a modified white hole. We obtain new possible mathematical connections with some sectors of Number Theory, Ramanujan Recurring Numbers, DN Constant and String Theory, that enable us to extract the quantum geometrical properties of these thermodynamic equations and the implication to the quantum vacuum spacetime geometry of our early universe as they act as the constraints to the nature of quantum gravity of the universe.

Fabricating a Micro Electromagnetic Actuator with High Energy Density

This paper introduces a new technology to fabricate a micro electromagnetic actuator with high energy density without an enclosed magnetic circuit. This technology includes fabricating multi-turns planar micro coils and fabricating the thick magnetic （NiFe） core on the silicon wafer. The multi-turns planar micro coils are fabricated by the electroplating method from the surface along the line and by dynamically controlling the current density of the copper electrolytes. In order to fabricate thick NiFe plating,the adhesion properties between the NiFe plating and the silicon substrates are improved by changing the surface roughness of the silicon substrates and increasing the thickness of the seed layer. Furthermore,the micro electromagnetic actuator is tested and the energy density of the actuator is evaluated by force testing. The experiments show that the microactuator is efficient in producing high magnetic energy density and high magnetic force.

Effects of laser energy density on forming accuracy and tensile strength of selective laser sintering resin coated sands

Baozhu sand particles with size between 75 μm and 150 μm were coated by resin with the ratio of 1.5 wt.% of sands. Laser sintering experiments were carried out to investigate the effects of laser energy density(E = P/v), with different laser power(P) and scanning velocity(v), on the dimensional accuracy and tensile strength of sintered parts. The experimental results indicate that with the constant scanning velocity, the tensile strength of sintered samples increases with an increase in laser energy density; while the dimensional accuracy apparently decreases when the laser energy density is larger than 0.032 J·mm-2. When the laser energy density is 0.024 J·mm-2, the tensile strength shows no obvious change; but when the laser energy density is larger than 0.024 J·mm-2, the sample strength is featured by the initial increase and subsequent decrease with simultaneous increase of both laser power and scanning velocity. In this study, the optimal energy density range for laser sintering is 0.024-0.032 J·mm-2. Moreover, samples with the best tensile strength and dimensional accuracy can be obtained when P = 30-40 W and v = 1.5-2.0 m·s-1. Using the optimized laser energy density, laser power and scanning speed, a complex coated sand mould with clear contour and excellent forming accuracy has been successfully fabricated.

From concept to reality-A review to the primary test stand and its preliminary application in high energy density physics

Pulsed power technology,whereas the electrical energy stored in a relative long period is released in much shorter timescale,is an efficient method to create high energy density physics(HEDP)conditions in laboratory.Around the beginning of this century,China Academy of Engineering Physics(CAEP)began to build some experimental facilities for HEDP investigations,among which the Primary Test Stand(PTS),a multi-module pulsed power facility with a nominal current of 10 MA and a current rising time~90 ns,is an important achievement on the roadmap of the electro-magnetically driven inertial confinement fusion(ICF)researches.PTS is the first pulsed power facility beyond 10 TW in China.Therefore,all the technologies have to be demonstrated,and all the engineering issues have to be overcome.In this article,the research outline,key technologies and the preliminary HEDP experiments are reviewed.Prospects on HEDP research on PTS and pulsed power development for the next step are also discussed.

Lithium metal batteries for high energy density:Fundamental electrochemistry and challenges

The dependence on portable devices and electrical vehicles has triggered the awareness on the energy storage systems with ever-growing energy density.Lithium metal batteries(LMBs)has revived and attracted considerable attention due to its high volumetric(2046 m Ah cm-3),gravimetric specific capacity(3862 m Ah g^(-1))and the lowest reduction potential(-3.04 V vs.SHE.).However,during the electrochemical process of lithium anode,the growth of lithium dendrite constitutes the biggest stumbling block on the road to LMBs application.The undesirable dendrite not only limit the Coulombic efficiency(CE)of LMBs,but also cause thermal runaway and other safety issues due to short-circuits.Understanding the mechanisms of lithium nucleation and dendrite growth provides insights to solve these problems.Herein,we summarize the electrochemical models that inherently describe the lithium nucleation and dendrite growth,such as the thermodynamic,electrodeposition kinetics,internal stress,and interface transmission models.Essential parameters of temperature,current density,internal stress and interfacial Li+flux are focused.To improve the LMBs performance,state-of-the-art optimization procedures have been developed and systematically illustrated with the intrinsic regulation principles for better lithium anode stability,including electrolyte optimization,artificial interface layers,threedimensional hosts,external field,etc.Towards practical applications of LMBs,the current development of pouch cell LMBs have been further introduced with different assembly systems and fading mechanism.However,challenges and obstacles still exist for the development of LMBs,such as in-depth understanding and in-situ observation of dendrite growth,the surface protection under extreme condition and the self-healing of solid electrolyte interface.

Superior corrosion resistance-dependent laser energy density in(CoCrFeNi)95Nb5 high entropy alloy coating fabricated by laser cladding

(CoCrFeNi)95Nb5 high entropy alloy(HEA)coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology.These(CoCrFeNi)95Nb5 HEA coatings possess excellent properties,particularly corrosion resistance,which is clearly superior to that of some typical bulk HEA and common engineering alloys.In order to obtain appropriate laser cladding preparation process parameters,the effects of laser energy density on the microstructure,microhardness,and corrosion resistance of(CoCrFeNi)95Nb5 HEA coating were closely studied.Results showed that as the laser energy density increases,precipitation of the Laves phase in(CoCrFeNi)95Nb5 HEA coating gradually decreases,and diffusion of the Fe element in the substrate intensifies,affecting the integrity of the(CoCrFeNi)95Nb5 HEA.This decreases the microhardness of(CoCrFeNi)95Nb5 HEA coatings.Moreover,the relative content of Cr2O3,Cr(OH)3,and Nb2O5 in the surface passive film of the coating decreases with increasing energy density,causing corrosion resistance to decrease.This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology,which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.

Experimental study on mechanism of influence of laser energy density on surface quality of Ti-6Al-4V alloy in selective laser melting

This experiment obtained different laser energy density(LED) by changing SLM molding process parameters.The surface morphology, surface quality, and microstructure of as-fabricated samples were studied. The effects of scanning speed, hatching space, and laser power on surface quality were analyzed, and the optimal LED range for surface quality was determined. The results show that pores and spherical particles appear on the sample’s surface when low LED is applied, while there are lamellar structures on the sides of the samples. Cracks appear on the sample’s surface,and the splash phenomenon increases when a high LED is taken. At the same time, a large amount of unmelted powder adhered to the side of the sample. The surface quality is the best when the LED is 150-170 J/mm^(3). The preferred hatch space is currently 0.05-0.09 mm, the laser power is 200-350 W, and the average surface roughness value is(15.1±3) μm.The average surface hardness reaches HV404±HV3, higher than the forging standard range of HV340-HV395.Increasing the LED within the experiment range can increase the surface hardness, yet an excessively high LED will not further increase the surface hardness. The microstructure is composed of needle-like α’-phases with a length of about 20μm, in a crisscross ‘N’ shape, when the LED is low. The β-phase grain boundary is not obvious, and the secondaryphase volume fraction is high;when the LED is high, the α’-phase of the microstructure is in the form of coarse slats, and the secondary-phase is composed of a small amount of secondary α’-phase, the tertiary α’-phase and the fourth α’-phase disappear, and the volume fraction of the secondary-phase becomes low.

3D Printing of NiCoP/Ti3C2 MXene Architectures for Energy Storage Devices with High Areal and Volumetric Energy Density

Designing high-performance electrodes via 3D printing for advanced energy storage is appealing but remains challenging.In normal cases,light-weight carbonaceous materials harnessing excellent electrical conductivity have served as electrode candidates.However,they struggle with undermined areal and volumetric energy density of supercapacitor devices,thereby greatly impeding the practical applications.Herein,we demonstrate the in situ coupling of NiCoP bimetallic phosphide and Ti3C2 MXene to build up heavy NCPM electrodes affording tunable mass loading throughout 3D printing technology.The resolution of prints reaches 50μm and the thickness of device electrodes is ca.4 mm.Thus-printed electrode possessing robust open framework synergizes favorable capacitance of NiCoP and excellent conductivity of MXene,readily achieving a high areal and volumetric capacitance of 20 F cm^-2 and 137 F cm^-3 even at a high mass loading of^46.3 mg cm^-2.Accordingly,an asymmetric supercapacitor full cell assembled with 3D-printed NCPM as a positive electrode and 3D-printed activated carbon as a negative electrode harvests remarkable areal and volumetric energy density of 0.89 mWh cm^-2 and 2.2 mWh cm^-3,outperforming the most of state-of-the-art carbon-based supercapacitors.The present work is anticipated to offer a viable solution toward the customized construction of multifunctional architectures via 3D printing for high-energy-density energy storage systems.

Boosting Pseudocapacitive Behavior of Supercapattery Electrodes by Incorporating a Schottky Junction for Ultrahigh Energy Density

Pseudo-capacitive negative electrodes remain a major bottleneck in the development of supercapacitor devices with high energy density because the electric double-layer capacitance of the negative electrodes does not match the pseudocapacitance of the corresponding positive electrodes.In the present study,a strategically improved Ni-Co-Mo sulfide is demonstrated to be a promising candidate for high energy density supercapattery devices due to its sustained pseudocapacitive charge storage mechanism.The pseudocapacitive behavior is enhanced when operating under a high current through the addition of a classical Schottky junction next to the electrode-electrolyte interface using atomic layer deposition.The Schottky junction accelerates and decelerates the diffusion of OH-/K+ions during the charging and discharging processes,respectively,to improve the pseudocapacitive behavior.The resulting pseudocapacitive negative electrodes exhibits a specific capacity of 2,114 C g^(-1)at 2 A g^(-1)matches almost that of the positive electrode’s 2,795 C g^(-1)at 3 A g^(-1).As a result,with the equivalent contribution from the positive and negative electrodes,an energy density of 236.1 Wh kg^(-1)is achieved at a power density of 921.9 W kg^(-1)with a total active mass of 15 mg cm-2.This strategy demonstrates the possibility of producing supercapacitors that adapt well to the supercapattery zone of a Ragone plot and that are equal to batteries in terms of energy density,thus,offering a route for further advances in electrochemical energy storage and conversion processes.

High energy density physics with intense ion beams

We review the development of High Energy Density Physics(HEDP)with intense heavy ion beams as a tool to induce extreme states of matter.The development of this field connects intimately to the advances in accelerator physics and technology.We will cover the generation of intense heavy ion beams starting from the ion source and follow the acceleration process and transport to the target.Intensity limitations and potential solutions to overcome these limitations are discussed.This is exemplified by citing examples from existing machines at the Gesellschaft fur Schwerionenforschung(GSI-Darmstadt),the Institute of Theoretical and Experimental Physics in Moscow(ITEP-Moscow),and the Institute of Modern Physics(IMP-Lanzhou).Facilities under construction like the FAIR facility in Darmstadt and the High Intensity Accelerator Facility(HIAF),proposed for China will be included.Developments elsewhere are covered where it seems appropriate along with a report of recent results and achievements.

Bi Nanoparticles Anchored in N-Doped Porous Carbon as Anode of High Energy Density Lithium Ion Battery

A novel bismuth–carbon composite, in which bismuth nanoparticles were anchored in a nitrogen-doped carbon matrix(Bi@NC), is proposed as anode for high volumetric energy density lithium ion batteries(LIBs).Bi@NC composite was synthesized via carbonization of Zn-containing zeolitic imidazolate(ZIF-8) and replacement of Zn with Bi, resulting in the N-doped carbon that was hierarchically porous and anchored with Bi nanoparticles. The matrix provides a highly electronic conductive network that facilitates the lithiation/delithiation of Bi.Additionally, it restrains aggregation of Bi nanoparticles and serves as a buffer layer to alleviate the mechanical strain of Bi nanoparticles upon Li insertion/extraction.With these contributions, Bi@NC exhibits excellent cycling stability and rate capacity compared to bare Bi nanoparticles or their simple composites with carbon. This study provides a new approach for fabricating high volumetric energy density LIBs.

A strategy to achieve high loading and high energy density Li-S batteries

Lithium-sulfur(Li-S) batteries are one of the most promising rechargeable storage devices due to the high theoretical energy density.However,the low areal sulfur loading impedes their commercial development.Herein,a 3 D free-standing sulfur cathode scaffold is rationally designed and fabricated by coaxially coating polar Ti_3 C_2 T_x flakes on sulfur-impregnated carbon cloth(Ti_3 C_2 T_x@S/CC) to achieve high loading and high energy density Li-S batteries,in which,the flexible CC substrate with highly porous structure can accommodate large amounts of sulfur and ensure fast electron transfer,while the outer-coated Ti_3 C_2 T_x can serve as a polar and conductive protective layer to further promote the conductivity of the whole electrode,achieve physical blocking and chemical anchoring of lithium-polysulfides as well as catalyze their conversion.Due to these advantages,at a sulfur loading of 4 mg cm^(-2),Li-S cells with Ti_3 C_2 T_x@S/CC cathodes can deliver outstanding cycling stability(746.1 mAh g^(-1) after 200 cycles at1 C),superb rate performance(866.8 mAh g^(-1) up to 2 C) and a high specific energy density(564.2 Wh kg^(-1) after 100 cycles at 0.5 C).More significantly,they also show the commercial potential that can compete with current lithium-ion batteries due to the high areal capacity of 6.7 mAh cm^(-2) at the increased loading of 8 mg cm^(-2).

Constructing nanocomposites with robust covalent connection between nanoparticles and polymer for high discharged energy density and excellent tensile properties

High discharged energy density and excellent flexible properties in dielectric materials are significantly sought to meet the rapid advancements in the electronics industry. In this study, covalent bonds are constructed between poly(vinylidene fluoride-chlorotrifluoroethylene), which contains olefinic bonds, and thiol-modified BaTiO_(3) at the interface before the nanocomposite films are fabricated. The presence of the covalent bonds is proved to promote the dispersibility of the modified BaTiO_(3) and enhance the interfacial adhesion between the modified BaTiO_(3) and the polymer, followed by a remarkably positive effect in suppressing the dielectric loss(tanδ) and increasing the breakdown strength(Eb) of the nanocomposite films. In addition, the cross-linking treatment in the preparation process is found to be favourable for improving the mechanical properties of the nanocomposite films, which benefits the enhancement of Eb. Furthermore, at 400% elongation, the stretched nanocomposite film doped with 5 vol% modified BaTiO_(3) exhibits an Eb15.6% greater than that of the unstretched film, and the discharged energy density reaches 11.4 J/cm^(3) with a high discharge energy efficiency of 84.5%. This study provides a novel strategy for preparing flexible nanocomposites with powerful interfacial adhesion at high filler content to achieve high discharged energy density.

Application-oriented hydrolysis reaction system of solid-state hydrogen storage materials for high energy density target:A review

Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen capacity.Hydrolysis reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable applications.At present,most of review work focuses on the improvement of material performance,especially the catalysts design.This part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical applications.Different operation modes of hydrolysis reaction have an impact on hydrogen capacity to various degrees.For example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the reaction.Therefore,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS materials.In this paper,the operation modes of hydrolysis reaction and their practical applications are mainly reviewed.The implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy density.The current challenges and future directions are also discussed.