Anode-Electrolyte Interface Chemistry for Low-Impedance Solid-State Batteries
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Solution Overview
Problem
The application of a lithium metal anode to a phthalocyanine solid-state electrolyte results in high interfacial impedance due to the formation of a solid electrolyte interphase with electrochemical characteristics not compatible with fast Li-ion transport, particularly because phthalocyanine SSEs are semi-crystalline and non-ductile, preventing good electrical contact.
Innovation Solution
A chemical additive is introduced in micro-liter quantities to the surface of the phthalocyanine SSE before adding the lithium metal anode, forming a solid electrolyte interphase that facilitates fast Li-ion transport and good electronic insulation, eliminating the need for the SSE to be ductile and flow under high pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium metal anode is applied to a phthalocyanine solid-state electrolyte, then the battery structure is formed, but high interfacial impedance occurs due to incompatible SEI electrochemical characteristics
Solution Approach 1:
A chemical additive (LiFSI in DME) is introduced as an intermediary substance between the lithium metal anode and the phthalocyanine SSE. This additive reacts with the SSE surface to form a modified SEI layer that serves as a mediator, enabling fast Li-ion transport while maintaining good electronic insulation. The intermediary chemical layer resolves the incompatibility between the native SEI and fast ion transport requirements.
Solution Approach 2:
The electrochemical characteristics of the SEI layer are changed by introducing the chemical additive. The additive modifies the composition and structure of the SEI, transforming it from a high-impedance native layer to a low-impedance engineered layer with suitable Li-ion conductivity. This parameter change in the SEI's electrochemical properties resolves the impedance issue.
2Productivity
If phthalocyanine SSE is used, then the battery is formed, but fast Li-ion transport is hindered because the SSE is semi-crystalline and non-ductile
Solution Approach 1:
The chemical additive forms an intermediary SEI layer that facilitates Li-ion transport without requiring the bulk SSE to be ductile. This mediator layer provides the necessary ion conductivity interface, decoupling the transport rate from the bulk material's ductility requirements.
Solution Approach 2:
The invention applies local quality modification by treating only the surface region of the SSE with the chemical additive. The SEI layer formed at this local interface has different properties (high Li-ion conductivity) than the bulk SSE material. This localized modification enables fast transport at the critical interface without changing the bulk SSE's semi-crystalline structure.
3Ease of manufacture
If traditional mechanical connection methods are used, then the anode and electrolyte are connected, but the SSE must be ductile and flow under high pressure
Solution Approach 1:
The invention replaces the mechanical connection approach (requiring ductile SSE that flows under pressure) with a chemical connection approach. The chemical additive reacts with the SSE surface to form a bonded SEI layer, substituting mechanical bonding with chemical bonding. This eliminates the need for high-pressure ductile forming while achieving stable connection.
Solution Approach 2:
The chemical additive serves as a mediator that enables connection without mechanical pressure. Instead of forcing ductile SSE to flow and bond mechanically, the additive chemically reacts with the SSE surface to create a bonded interface, replacing the mechanical connection mechanism with a chemical one.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This chemical connection process achieves a solid-state battery with a discharge rate of up to 97% capacity over 2.83 hours at 23°C and 80% capacity at 0°C, providing a stable and efficient electronic contact between the anode and phthalocyanine SSE.
Implementation Method 1
A chemical additive is introduced in micro-liter quantities to the surface of the phthalocyanine SSE prior to the addition of the lithium metal anode, forming a solid electrolyte interphase
Data Source
AI summary
The present invention relates to a solid-state battery that is based on a phthalocyanine solid-state electrolyte/anode connection that is chemically obtained. Such chemical connection process yields a solid electrolyte interphase that connects the solid-state battery's phthalocyanine solid-state electrolyte and anode. Unlike other processes for forming solid-state electrolyte/anode connections, the present chemical process does not require that solid-state electrolyte be ductile and flow under high pressure.