锂硫银锗矿固态电解质研究进展

全固态电池因其较高的安全性和能量密度而成为下一代电动汽车和智能电网用储能器件的重点研究方向之一。开发具有高室温锂离子电导率、化学/电化学稳定性优异、对电极材料兼容性优异等特点的固态电解质材料是推动全固态电池发展的重要研究课题之一。硫化物电解质因其相对较高的室温电导率(~10^(-3) S·cm^(-1))、较低的电解质/电极固-固界面阻抗等优点而在众多无机固体电解质材料中成为研究热点。本文基于作者多年研究成果和当前国内外发表的相关工作,从电解质的结构、离子传导、合成、综合性能改善及在全固态电池中的应用等方面系统总结了锂硫银锗矿固态电解质材料研究,并分析了该类电解质面临的问题和挑战,最后探讨了其未来可能的研究方向和发展趋势。

卤化物固态电解质研究进展

全固态电池因其高能量密度和高安全性而成为具有发展前景的下一代储能技术。开发具有高室温离子电导率、优异化学/电化学稳定性、良好正/负极兼容性的固态电解质是实现全固态电池实用化的关键。卤化物固态电解质因其优异的电化学窗口、高正极稳定性、可接受的室温锂离子电导率等优势,受到了广泛的关注。本文通过对近年来卤化物电解质的相关研究进行总结,综述了该类电解质的组成、结构、离子传导路径及制备方法,并分析了金属卤化物电解质的电导率、稳定性特点,归纳了近年来该电解质在全固态电池中具有代表性的应用,并基于以上总结和分析,指出了卤化物固态电解质的研究难点及发展方向。

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.

Enabling superior electrochemical performance of NCA cathode in Li_(5.5)PS_(4.5)Cl_(1.5)-based solid-state batteries with a dual-electrolyte layer

LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)(NCA) is a promising cathode for sulfide-based solid-state lithium batteries(ASSLBs)profiting from its high specific capacity and voltage plateau, which yielding high energy density. However, the inferior interfacial stability between the bare NCA and sulfides limits its electrochemical performance. Hereien, the dual-electrolyte layer is proposed to mitigate this effect and enhance the battery performances of NCA-based ASSLIBs. The Li_(3)InCl_6 wih high conductivity and excellent electrochemcial stability act both as an ion additives to promote Li-ion diffusion across the interface in the cathode and as a buffer layer between the cathode layer and the solid electrolyte layer to avoid side reactions and improve the interface stability. The corresponding battery exhibits high discharge capacities and superior cyclabilities at both room and elevated temperatures. It exhibits discharge performance of 237.04 and216.07 m Ah/g at 0.1 and 0.5 C, respectively, when cycled at 60 ℃, and sustains 95.9% of the capacity after100 cycles at 0.5 C. The work demonstrates a simple strategy to ensure the superior performances of NCA in sulfide-based ASSLBs.

Revealing milling durations and sintering temperatures on conductivity and battery performances of Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte

Halide electrolytes in solid-state batteries with excellent oxidative stability and high ionic conductivity have been well reported recently.However,the high-cost rare-earth elements and long duration of highrotation milling procure are the major obstacles.Herein,we have successfully synthesized the low cost Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte consisting of abundant elements with comparable Li-ion conductivity in a short milling duration of 4 h.Phase transition of the annealed sample was also carefully investigated.Li Ni_(0.6)Co_(0.2)Mn_(0.2)O_(2)/Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)/Li_(5.5)PS_(4.5)Cl_(1.5)/In-Li batteries using different halide electrolytes were constructed and cycled at different voltage windows.Solid-state battery using Li_(2.25)Zr_(0.75)Fe_(0.25)Cl_(6)electrolyte obtained from long milling duration delivers higher discharge capacities and superior capacity retention than shorter milling time between 3.0 and 4.3 V.It delivers much higher discharge capacity when cycled at elevated temperature(60℃)and suffers fast capacity degradation when the upper cut-off voltage increases to 4.5 V at the same current density.This work provides an efficiency synthesis strategy for halide solid electrolyte and studies its applications in all-solid-state batteries in a wide temperature range.

Revealing performance of 78Li_(2)S-22P_(2)S_(5) glass ceramic based solid-state batteries at different operating temperatures

78Li_(2)S-22P_(2)S_(5) are sulfide electrolytes with high lithium-ion conductivity and wide electrochemical windows in the Li_(2)S-P_(2)S_(5) system,making them attractive solid electrolytes for ASSLBs.However,the role and potential of 78Li_(2)S-22P_(2)S_(5) solid electrolytes over a wide temperature range are still not fully understood.Therefore,we constructed solid-state batteries with NCM622 as the positive electrode and 78Li_(2)S-22P_(2)S_(5) glass-ceramics as the electrolyte to investigate in depth the differences in battery performance over a wide temperature range and their intrinsic mechanisms.The in-situ impedance and relaxation time distribution (DRT) demonstrated the electrochemical stability of the electrolyte over a wide temperature range,while the in-situ stacking pressure observed a large volume change during cycling at 60℃,leading to local solid-solid contact failure and poor cycling stability.This study provides insight into the advantages and problems of 78Li_(2)S-22P_(2)S_(5) in the wide temperature range as well as a basis for the construction of ASSLBs with high energy density and long cycle life.

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.

Enabling ultrafast lithium-ion conductivity of Li_(2)ZrCl_(6) by indium doping

Solid-state batteries with high energy density and safety are promising next-generation battery systems.However,lithium oxide and lithium sulfide electrolytes suffer low ionic conductivity and poor electrochemical stability,respectively.Lithium halide solid electrolyte shows high conductivity and good compatibility with the pristine high-voltage cathode but limited applications due to the high price of rare metal.Zr-based lithium halides with low cost and high stability possess great potential.Herein,a small amount of In^(3+)is introduced in Li_(2)ZrCl_(6) to synthesize Li_(2.25)Zr_(0.75)In_(0.25)Cl_(6) electrolytes with a high room temperature Li-ion conductivity of 1.08 mS/cm.Solid-state batteries using Li_(2.25)Zr_(0.75)In_(0.25)Cl_(6)/Li_(5.5)PS_(4.5)Cl_(1.5) bilayer solid electrolytes combined with Li-In anode and pristine LiNi_(0.7)Mn_(0.2)Co_(0.1)O_(2) cathode deliver high initial discharge capacities under different cut-off voltages.This work provides an effective strategy for enhancing the conductivity of Li2ZrCl6 electrolytes,promoting their applications in solid-state batteries.

Revealing the size effect of Fe S2on solid-state battery performances at different operating temperatures

FeS_(2) shows significant potential as cathode material for all-solid-state lithium batteries(ASSLBs)due to its high theoretical specific capacity,low cost,and environmental friendliness.However,the poor ion/electron conductivity and large volume variation effect of FeS_(2) inhibit its practical applications.Here,the influence of particle size of FeS_(2) on the corresponding sulfide-based solid-state batteries is carefully investigated by tuning FeS_(2) size.Moreover,low operating temperature is chosen to mitigate the large volume changes during cycling in the battery.S-FeS_(2) with smaller particle sizes delivers superior electrochemical performances than that of the larger L-FeS_(2) in Li_(5.5)PS_(4.5)Cl_(1.5)-based ASSLBs under different operating temperatures.S-FeS_(2) shows stable discharge capacities during 50 cycles with a current density of 0.1 m A/cm^(2)under -20℃.When the current density rises to 1.0 m A/cm^(2),it delivers an initial discharge capacity of 146.9 m Ah/g and maintains 63% of the capacity after 100 cycles.This work contributes to constructing ASSLBs enables excellent electrochemical performances under extreme operating temperatures.