Synergy of I-Cl co-occupation on halogen-rich argyrodites and resultant dual-layer interface for advanced all-solid-state Li metal batteries

The(electro)chemical stability and Li dendrite suppression capability of sulfide solid electrolytes(SEs)need further improvement for developing all-solid-state Li batteries(ASSLBs).Here,we report advanced halogen-rich argyrodites via I and Cl co-occupation on the crystal lattice.Notably,a proper I content forms a single phase,whereas an excessive I causes precipitation of two argyrodite phases like a superlattice structure.The resultant synergistic effect of the optimized composition allows to gain high ionic conductivities at room temperature and-20℃,and enhances the(electro)chemical stability against Li and Li dendrite suppression capability.The Li|argyrodite interface is very sensitive to the ratio of I and Cl.A LiCl-and LiI-rich double-layer interface is observed from the cell using the SE with optimized composition,whereas too high I content forms only a single interface layer with a mixture of Lil and LiCl.This double-layer interface is found to effectively mitigate the Li/SE reaction.The proper designed argyrodite enables ASSLBs to achieve good electrochemical properties at a broad temperature range regardless of the electrode materials.This co-occupation strategy provides a novel exploration for advanced halogen-rich argyrodite system.

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.

Sn-O dual-doped Li-argyrodite electrolytes with enhanced electrochemical performance

As a type of candidate for all-solid-state Li batteries,argyrodite solid electrolytes possess high ionic conductivity,but poor compatibility against Li metal.Here,we report novel Li_(6) PS_(5) I-based argyrodite sulfides with Sn-O dual doping,which is a powerful solution to comprehensively improve the performance of a material.The combination of O and Sn-aliovalent doping not only enables an improved ionic conductivity but more importantly realizes an intensively enhanced interfacial compatibility between argyrodite and Li metal and Li dendrite suppression capability.The assembled battery with Sn-O dual-doped electrolyte and Li anode demonstrates high capacity and decent cycling stability.Dual doping is thus believed to be an effective way to develop high performance sulfide solid electrolytes.

Lithium-site substituted argyrodite-type Li_(6)PS_(5)I solid electrolytes with enhanced ionic conduction for all-solid-state batteries

Argyrodites,Li_(6)PS_(5)X(X=Cl,Br,I),have piqued the interest of researchers by offering promising lithium ionic conductivity for their application in all-solid-state batteries(ASSBs).However,other than Li_(6)PS_(5)Cl(651Cl)and Li_(6)PS_(5)Br(651Br),Li_(6)PS_(5)I(651I)shows poor ionic conductivity(10^(-7)S cm^(-1)at 298 K).Herein,we present Al-doped 651I with I^(-)/S^(2-)site disordering to lower activation energy(Ea)and improve ionic conductivity.They formed argyrodite-type solid solutions with a composition of(Li_(6–3x)Al_(x))PS_(5)I in 0≤x≤0.10,and structural analysis revealed that Al^(3+)is located at Li sites.Also,the Al-doped samples contained anion I^(-)/S^(2-)site disorders in the crystal structures and smaller lattice parameters than the non-doped samples.Impedance spectroscopy measurements indicated that Al-doping reduced the ionic diffusion barrier,Ea,and increased the ionic conductivity to 10^(-5)S cm^(-1);the(Li5.7Al0.1)PS5I had the highest ionic conductivity in the studied system,at 2.6×10^(-5)S cm^(-1).In a lab-scale ASSB,with(Li_(5.7)Al_(0.1))PS_(5)I functioned as a solid electrolyte,demonstrating the characteristics of a pure ionic conductor with negligible electronic conductivity.The evaluated ionic conduction is due to decreased Li+content and I^(-)/S^(2-)disorder formation.Li-site cation doping enables an in-depth understanding of the structure and provides an additional approach to designing betterperforming SEs in the argyrodite system.

Chlorine-rich lithium argyrodites enables superior performances for solid-state Li-Se batteries at wide temperature range

All-solid-state Li-Se battery shows great potential as a candidate for next-generation energy storage devices due to its high energy density and safety.However,the low ionic conductivity of the solid electrolytes and large volume changes of Se active materials are two of the major issues that limit its applications.Herein,a simple solid-state reaction method is applied to synthesize chlorine-rich argyrodite Li_(5.5)PS_(4.5)CI_(1.5)electrolyte with high conductivity of 6.25 mS·cm^(-1)at room temperature.Carbon nanotube(CNT)is introduced as the host for Se to obtain Se/CNT composite with both enhanced electronic conductivity and lower volume expansion during the electrochemical reaction process.All-solid-state Li-Se battery using Li_(5.5)PS_(4.5)CI_(1.5)as solid electrolyte combined with Se/CNT cathode and Li-In anode shows a discharge capacity of 866 mAh·g-1for the 2nd cycle under0.433 mA·cm-2at room temperature.Moreover,the assembled battery delivers a high discharge capacity of1026 mAh·g^(-1)for the 2nd cycle when cycled at the same current density at 60℃and maintains a discharge capacity of 380 mAh·g^(-1)after 150 cycles.Owing to the high Li-ion conductivity of Li_(5.5)PS_(4.5)CI_(1.5)electrolyte,the assembled battery displays a high discharge capacity of 344 mAh·g^(-1)under 0.113 mA·cm^(-2)at-20℃C and remains 66.1%after200 cycles.In addition,this all-solid-state Li-Se battery shows ultralong cycling performances up to 1000 cycles under 0.433 mA·cm^(-2)at-20℃.This work offers the design clue to fabricate the all-solid-state Li-Se battery workable at different operating temperatures with an ultralong cycling life.

Tuning Solid Interfaces via Varying Electrolyte Distributions Enables High-Performance Solid-State Batteries

Solid/solid interface is the major challenge for high-performance solid-state batteries.Solid electrolytes(SEs)play a crucial role in the fabrication of effective interfaces in solid-state batteries.Herein,the electrolyte distribution with varied particle sizes is tuned to construct solid-state batteries with excellent performance at different operating temperatures.Solid-state batteries with the configuration S/L(small-sized SE in composite cathode and large-sized SE in electrolyte layer)show the best performance at room temperature(168 mA h g^(−1) at 0.2 C,retention of 99%,100 cycles)and−20°C(89 mA h g^(−1) at 0.05 C),while the configuration S/S displays better performance at elevated temperature.The superior performance of S/L battery is associated with faster lithium-ion dynamics due to the better solid/solid interface between active materials and electrolytes.Moreover,the inferior performance at 60℃is caused by the formation of voids and cracks in the electrolyte layer during cycling.In contrast,the S/S battery delivers superior performance at elevated operating temperature because of the integrated structure.This work confirms that tailoring electrolyte size has significant effect on fabricating all-climate solid-state batteries.

Construction of LiCl/LiF/LiZn hybrid SEI interface achieving high-performance sulfide-based all-solid-state lithium metal batteries

Sulfide-based all-solid-state lithium metal batteries(ASSLMBs)have received extensive attention due to their high energy density and high safety,while the poor interface stability between sulfide electrolyte and lithium metal anode limits their development.Hence,a hybrid SEI(LICl/Li F/Li Zn)was constructed at the interface between Li_(5.5)PS_(4.5)Cl_(1.5)sulfide electrolyte and lithium metal.The Li Cl and Li F interface phases with high interface energy effectively induce the uniform deposition of Li^(+)and reduce the overpotential of Li^(+)deposition,while the Li Zn alloy interface phase accelerates the diffusion of lithium ions.The synergistic effect of the above functional interface phases inhibits the growth of lithium dendrites and stabilizes the interface between the sulfide electrolyte and lithium metal.The hybrid SEI strategy exhibits excellent electrochemical performance on symmetric batteries and all-solid-state batteries.The symmetrical cell exhibits stable cycling performance over long duration over 500 h at 1.0 mA cm^(-2).Moreover,the LiNbO_(3)@NCM712/Li_(5.5)PS_(4.5)Cl_(1.5)/Li-10%Zn F_(2)battery exhibits excellent cycle stability at a high rate of 0.5 C,with a capacity retention rate of 76.4%after 350 cycles.

Mitigation of the Instability of Ultrafast Li-Ion Conductor Li_(6.6)Si_(0.6)Sb_(0.4)S_(5)I Enables High-Performance All-Solid-State Batteries

Solid-state batteries with excellent safety and high energy density display great potential as next-generation energy storage devices.However,few solid electrolytes simultaneously possess high ionic conductivity and good chemical and electrochemical stability.Herein,pure argyrodite Li_(6.6)Si_(0.6)Sb_(0.4)S_(5)I electrolyte with high Li-ion conductivity(9.0 mS cm−1)and poor stability is successfully synthesized via the typical mechanochemical route.Interfacial instability of this electrolyte with different electrode materials is investigated.A highly conductive Li_(3)InCl_(6)electrolyte,with a wide voltage window and excellent chemical and electrochemical stability,active material,and conductive carbon are introduced in the battery configuration,resulting in superior electrochemical performances with the bare LiNi_(0.7)Mn_(0.2)Co_(0.1)O_(2)cathode.The corresponding battery delivers a discharge capacity of 162.1 mAh g^(−1)at 0.5C and maintains 83.8%of the capacity after 200 cycles at room temperature.Moreover,this battery with a cathode mass loading of 6.37 mg cm−2 displays discharge capacities of 197.5 and 73.4 mAh g^(−1)at the beginning when cycled at 0.5C and 0.1C under the operating temperature of 60 and−20℃,respectively.The battery also achieved superior stablecycling performances at both temperatures.Due to the fast ionic conductivity from Li_(6.6)Si_(0.6)Sb_(0.4)S_(5)I and high electronic conductivity from carbon in the cathode,the thick-electrode configurations with huge mass loadings of 50.96 and 76.43 mg cm^(−2)also exhibit good capacities and highly reversible cyclability.This work provides a guideline for enabling superior conducting sulfide electrolytes with poor stability in thick-electrode configuration solid-state batteries.