Enabling Argyrodite Sulfides as Superb Solid-State Electrolyte with Remarkable Interfacial Stability Against Electrodes

While argyrodite sulfides are getting more and more attention as highly promising solid-state electrolytes(SSEs)for solid batteries,they also suffer from the typical sulfide setbacks such as poor electrochemical compatibility with Li anode and high-voltage cathodes and serious sensitivity to humid air,which hinders their practical applications.Herein,we have devised an effective strategy to overcome these challenging shortcomings through modification of chalcogen chemistry under the guidance of theoretical modeling.The resultant Li_(6.25)PS_(4)O_(1.25)Cl_(0.75)delivered excellent electrochemical compatibility with both pure Li anode and high-voltage LiCoO_(2)cathode,without compromising the superb ionic conductivity of the pristine sulfide.Furthermore,the current SSE also exhibited highly improved stability to oxygen and humidity,with further advantage being more insulating to electrons.The remarkably enhanced compatibility with electrodes is attributed to in situ formation of helpful electrolyte–electrode interphases.The formation of in situ anode–electrolyte interphase(AEI)enabled stable Li plating/stripping in the Li|Li_(6.25)PS_(4)O_(1.25)Cl_(0.75)|Li symmetric cells at a high current density up to 1 mA cm^(-2)over 200 h and 2 mA cm^(-2)for another 100 h.The in situ amorphous nano-film cathode–electrolyte interphase(CEI)facilitated protection of the SSE from decomposition at elevated voltage.Consequently,the synergistic effect of AEI and CEI helped the LiCoO_(2)|Li_(6.25)PS_(4)O_(1.25)Cl_(0.75)|Li full-battery cell to achieve markedly better cycling stability than that using the pristine Li_(6)PS_(5)Cl as SSE,at a high area loading of the active cathode material(4 mg cm^(-2))in type-2032 coin cells.This work is to add a desirable SSE in the argyrodite sulfide family,so that high-performance solid battery cells could be fabricated without the usual need of strict control of the ambient atmosphere.

Recent advances based on Mg anodes and their interfacial modulation in Mg batteries

Magnesium(Mg)batteries(MBs),as post-lithium-ion batteries,have received great attention in recent years due to their advantages of high energy density,low cost,and safety insurance.However,the formation of passivation layers on the surface of Mg metal anode and the poor compatibility between Mg metal and conventional electrolytes during charge-discharge cycles seriously affect the performance of MBs.The great possibility of generating Mg dendrites has also caused controversy among researchers.Moreover,the regulation of Mg deposition and the enhancement of battery cycle stability is largely limited by interfacial stability between Mg metal anode and electrolyte.In this review,recent advances in interfacial science and engineering of MBs are summarized and discussed.Special attention is given to interfacial chemistry including passivation layer formation,incompatibilities,ion transport,and dendrite growth.Strategies for building stable electrode/interfaces,such as anode designing and electrolyte modification,construction of artificial solid electrolyte interphase(SEI)layers,and development of solid-state electrolytes to improve interfacial contacts and inhibit Mg dendrite and passivation layer formation,are reviewed.Innovative approaches,representative examples,and challenges in developing high-performance anodes are described in detail.Based on the review of these strategies,reference is provided for future research to improve the performance of MBs,especially in terms of interface and anode design.

Enabling High-Performance Sodium Battery Anodes by Complete Reduction of Graphene Oxide and Cooperative In-Situ Crystallization of Ultrafine SnO_(2)Nanocrystals

The main bottleneck against industrial utilization of sodium ion batteries(SIBs)is the lack of high-capacity electrodes to rival those of the benchmark lithium ion batteries(LIBs).Here in this work,we have developed an economical method for in situ fabrication of nanocomposites made of crystalline few-layer graphene sheets loaded with ultrafine SnO_(2)nanocrystals,using short exposure of microwave to xerogel of graphene oxide(GO)and tin tetrachloride containing minute catalyzing dispersoids of chemically reduced GO(RGO).The resultant nanocomposites(SnO_(2)@MWG)enabled significantly quickened redox processes as SIB anode,which led to remarkable full anode-specific capacity reaching 538 mAh g^(−1)at 0.05 A g^(−1)(about 1.45 times of the theoretical capacity of graphite for the LIB),in addition to outstanding rate performance over prolonged charge–discharge cycling.Anodes based on the optimized SnO_(2)@MWG delivered stable performance over 2000 cycles even at a high current density of 5 A g^(−1),and capacity retention of over 70.4%was maintained at a high areal loading of 3.4 mg cm^(−2),highly desirable for high energy density SIBs to rival the current benchmark LIBs.

Seamless Stitching of Redox Windows to Enable High-Voltage Resilient Solid Sodium Ion Batteries

While sulfide solid electrolytes such as Na_(11)Sn_(2)PS_(12)can allow fast transport of Na+ions,their utilization in solid sodium ion batteries is rather unsuccessful since they are not electrochemically compatible to both high-voltage cathodes and sodium metal anode.In this work,we devise an effective approach toward realizing solid sodium ion batteries,using the Na_(11)Sn_(2)PS_(12)electrolyte and slurry-coated NASICON-type Na_(3)MnTi(PO_(4))_(3)@C as high-voltage cathode,highly beneficial for low processing cost and high content/loading of active cathode matter.We report that through significantly improved integrity of electrolyte-cathode interface,such solid sodium ion batteries can deliver outstanding cycling and rate performance,with a charge voltage resilience up to 4.1 V,a high cathode discharge capacity of 128.7 mAh g^(-1)against the Na_(3)MnTi(PO_(4))_(3)@C in cathode is achieved at 0.05 C,and capacity retention ratio of 82%with a rate of 0.1 C is realized after prolonged cycling at room temperature.Besides,we demonstrate that such a solid sodium ion battery can even perform at a sub-zero Celsius temperature of-10℃,when the conventional control cell using liquid electrolyte completely fail to function.This work is to offer a dependable avenue in engineering next generation of safe solid ion batteries based on highly sustainable and much cheaper material resources.

Durable self-polishing antifouling Cu-Ti coating by a micron-scale Cu/Ti laminated microstructure design

Marine biofouling is a major issue deteriorating the service performance and lifespan of marine infrastructures.The development of a durable,long-term,and environment-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime engineering.Herein,we developed a Cu-Ti composite antifouling coating with micron-sized alternating laminated-structure of Cu/Ti by plasma spraying of mechanically mixed Cu/Ti powders.The coating was designed to enable controlled release of Cu ions through galvanic dissolution of Cu laminates from the Cu/Ti micro-galvanic cell in aqueous solution.Results showed that remarkable antifouling efficiency against bacterial survival and adhesion up to~100%was achieved for the Cu-Ti coating.Cu/Ti micro-galvanic cell was in-situ formed within Cu-Ti coating and responsible for its Cu ions release.The successive dissolution of Cu laminates resulted in the formation of micro-channels under Ti laminates near surface,which contributed to controlled slow Cu ions release and self-polishing effect.Thus,environment-friendly antifouling capability and∼200%longer antifouling lifetime than that of the conventional organic antifouling coatings can be achieved for the Cu-Ti coating.On the other hand,as compared to the conventional organic antifouling coatings,the Cu-Ti composite coating presented much higher mechanical durability due to its strong adhesion strength,excellent mechanical properties,and two orders lower wear rate.The present laminated Cu-Ti coating exhibits combination of outstanding antifouling performance and high mechanical durability,which makes this coating very potentially candidates in marine antifouling application.

In-plane grain boundary induced defect state in hierarchical NiCo-LDH and effect on battery-type charge storage

Domain boundaries are regarded as the effective active sites for electrochemical energy storage materials due to defects enrichment therein.However,layered double hydroxides(LDHs)tend to grow into single crystalline nano sheets due to their unique two-dimentional(2D)lattice structure.Previously,much efforts were made on the designing hierarchical structure to provide more exposed electroactive sites as well as accelerate the mass transfer.Herein,we demonstrate a strategy to introduce low angle grain boundary(LAGB)in the flakes of Ni/Co layered double hydroxides(NiCo-LDHs).These defect-rich nano flakes were self-assembled into hydrangea-like spheres that further constructed hollow cage structure.Both the formation of hierarchical structure and grain boundaries are interpreted with the synergistic effect of Ni2+/Co2+ratio in an“etching-growth”process.The domain boundary defect also results in the preferential formation of oxygen vacancy(Vo).Additionally,density functional theory(DFT)calculation reveals that Co substitution is a critical factor for the formation of adjacent lattice defects,which contributes to the formation of domains boundary.The fabricated battery-type Faradaic NiCo-LDH-2 electrode material exhibits significantly enhanced specific capacitance of 899 C·g^(−1)at a current density of 1 A·g^(−1).NiCo-LDH-2//AC asymmetric capacitor shows a maximum energy density of 101.1 Wh·kg^(−1)at the power density of 1.5 kW·kg^(−1).

Planar Li growth on Li_(21)Si_(5)modified Li metal for the stabilization of anode

Lithium(Li)metal is widely considered the ultimate anode for future rechargeable batteries.However,dendritic growth and related parasitic reactions during long-term cycling often lead to severe safety hazards and catastrophic failure.Herein,we fabricate a hybrid anode by coating single-phase Li_(21)Si_(5)on lithium metal.The resultant electrodes show a stable cycle and depressed polarization in symmetric and half cells.A planar plating/stripping behavior is observed on the modified anode.The investigation of the interplay of Li and Li_(21)Si_(5)shows relatively large adsorption energy in the Li-Si system.The deposition and stripping are surface processes,and Li_(21)Si_(5)maintains its intrinsic phase structure.The deposited Li layer around Li_(21)Si_(5)also has the advantage of diminished preferred orientation,which also contributes to the planar growth of Li.Both LiFePO4(LFP)and LiNi1/3Co1/3 Mn1/3O2(NCM)cathodes were applied to further demonstrate the enhanced rate and cycle performance.