Background

The stabilization of cathodes in all-solid state lithium batteries (ASSLBs) is critical to achieve compatible performance with commercial Li-ion batteries (LIBs) using liquid electrolytes. The ideal solid electrolytes (SEs) in the cathode layer must have high ionic conductivity (>10^-3 S cm^-1), chemical stability, a wide electrochemical stability window, and intimate contact with the cathode. Conventional superior ion-conduct SEs, like oxides and sulfides, are limited by insufficient interface contact or severe interface reaction. Extra interface engineering is necessary to achieve a stable interface. However, conventional approaches, like atomic layer deposition (ALD) and chemical vapor deposition (CVD), are generally limited by high cost. Wet chemical coating and dry mixing are challenged by the unconformable coating. Both ALD and wet coating meet challenges for scalability in the industry. Meanwhile, the coating materials generally deliver low ionic conductivities (10^-6~10^-9 S cm^-1), which cause sluggish reaction kinetics.

Technology Overview

This Northeastern University invention successfully employed a halide to achieve a stabilized cathode electrode and high-performance ASLB with cell-level energy density. The chosen halide is highlighted with outstanding ionic conductivity (>0.5 mS cm^‑1) under high potential, good stability with high voltage cathodes, and a wide electrochemical stability window (>5 V vs. Li+/Li). More importantly, through a water-mediated synthesis approach, the process is scalable, the mixing of halides with cathode is uniform, and accompanies intimate contact. Compared with directly using oxides, sulfides, or aforementioned interface engineering approaches, the presented invention is facile, scalable, highly efficient, and promising for industrial use.

Benefits

• Intimate contact at the interface on the cathode and therefore eliminates the need for an extra coating or interface engineering
• No high-cost facilities or high-temperature treatment needed
• The water-mediated approach shows potential in large-scale applications
• The ionic conductivity of the electrolyte is three to four orders higher than that of conventional coating materials
• Highly stable electrolyte
• Scalable, high performance and low cost

Applications

• Highly stable cathode for all-solid-state batteries in various applications:
  • Electric vehicle manufacturer, such as Tesla, Toyota, Nissan
  • Portable electronics manufacturer, such as apple, Samsung
• This water-mediated approach can also be applied in the fabrication of a thin solid electrolyte layer.

Opportunity

• Research Collaboration
• Licensing
• Commercial partner