Surface Engineering Strategy Enables 4.5 V Sulfide-Based All-Solid-State Batteries with High Cathode Loading and Long Cycle Life

Abstract

Sulfide-based all-solid-state lithium batteries (ASSLBs) with LiCoO 2 (LCO) operating at high voltage (≥4.5 V vs Li + /Li) hold promise in realizing high energy density while maintaining safety. Here, we propose a solid electrolyte coating strategy to stabilize the cathode electrolyte interface and demonstrate the benefit of lithium difluoro-(oxalate)borate (LiDFOB) as coating layer on the surface of Li 6 PS 5 Cl (LPSCl) to improve the performance of LCO at 4.5 V. 89.3% of initial discharge capacity can be retained after 1500 cycles at 1C (1C = 150 mA g −1 ). ASSLBs with high cathode loading (35.7 mg cm −2 ) could deliver an areal capacity over 6 mAh cm −2 (167 mAh g −1 ) at 0.1C and keep 85% capacity retention after 200 cycles at 0.3C. The investigation of the improvement mechanism further verifies that in situ decomposition of LiDFOB would build an (electro)chemomechanically stable interface, which not only suppresses interfacial side reactions but also buffers the cathode cracking.

Enhancement of the Li+ Conductivity of Li3AlF6 for Stable All-Solid-State Lithium-Ion Batteries

“…2 Solid electrolytes with high Li + conductivity are needed for the realization of all-solid-state LIBs, with oxideand sulfide-based ceramics being extensively studied. 3,4 Lithium hydrides also exhibit exceptionally high Li ductivities with excellent powder pressing abilities. 5,6 Recently, lithium metal halides have attracted attention owing to their high Li + conductivity combined with their nontoxic, nonflammable, and high powder-pressing abilities.…”

“…Furthermore, bipolar stacking of the cell can lead to further increase of the energy density . Solid electrolytes with high Li + conductivity are needed for the realization of all-solid-state LIBs, with oxide- and sulfide-based ceramics being extensively studied. , Lithium hydrides also exhibit exceptionally high Li + conductivities with excellent powder pressing abilities. , Recently, lithium metal halides have attracted attention owing to their high Li + conductivity combined with their nontoxic, nonflammable, and high powder-pressing abilities. The steep advances in halide materials have primarily risen from the study of Asano et al, who revealed the high Li + conduction of Li 3 YCl 6 and Li 3 YBr 6 .…”

Additive-Derived Surface Modification of Cathodes in All-Solid-State Batteries: The Effect of Lithium Difluorophosphate- and Lithium Difluoro(oxalato)borate-Derived Coating Layers

“…Various materials, including oxides, polymers, halides, and sulfides, are used as solid-state electrolytes in ASSBs. − Among these materials, sulfide-based solid electrolytes exhibit the highest ionic conductivity − and excellent formability, which enables efficient electrolyte–electrode contact. Consequently, among all the all-solid-state cells (ASSCs) reported to date, the performance of ASSCs utilizing sulfide-based solid electrolytes is the closest to that of commercially available LIBs. − However, sulfide-based solid electrolytes exhibit high reactivity and a relatively narrow voltage window of stability, resulting in electrolyte decomposition during cycling.…”

“…All-solid-state batteries (ASSBs), which contain nonflammable or flame-retardant solid electrolytes, comprise a new generation of rechargeable battery systems that exhibit a significantly lower risk of fire and explosion than commercial lithium-ion batteries (LIBs), which contain flammable organic-liquid electrolytes. − The enhanced safety features of ASSBs are expected to make them highly desirable for commercial use. Beyond their enhanced safety profile, ASSBs demonstrate great potential for maintaining high levels of performance even at extreme temperatures, both high and low. − These advantages also imply the possibility of simplifying the cooling and battery management systems, thereby increasing the energy density per ASSB pack.…”

Constructing Magnetic Ion Accelerator at Na2/3Ni1/3Mn2/3O2 Surface for Sodium Ion Batteries

“…In this regard, great attention has been paid to the design and construction of artificial layers since the advent of lithium-ion cathode materials in the 1970s, − which could be classified into two categories. One type could be summarized as a “passive” decoration layer, which mainly contributes as a physical barrier on the surface of an electrode material. − Another strategy is termed “active” materials, which are involved in constructing more robust and/or efficient functional interfaces with thermal, dynamic, , or electric fields − on the surface of cathodes besides the traditional physical separation effect between electrolyte and electrode, revealing the great potential of designing multifunctional interfaces with field effects.…”