Lithium Superionic Conductors With Stable, Low-Cost Electrolyte Chemistry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium superionic conductors face limitations such as high cost, instability, and compatibility issues with electrodes in all-solid-state rechargeable lithium-ion batteries, necessitating the development of new materials with improved phase and electrochemical stability, and high ionic conductivity.
Innovation Solution
The development of new earth-abundant lithium superionic conductors, Li3Y(PS4)2 and Li5PS4Cl2, derived from a high-throughput first principles screening approach, which predicts materials with enhanced Li+ conductivity and stability, and the application of aliovalent doping strategies to further enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing lithium superionic conductors (e.g., Li10GeP2S12, Li7P3S11) are used, then high ionic conductivity is achieved, but cost increases or stability deteriorates
Solution Approach 1:
The patent replaces expensive germanium (Ge) in Li10GeP2S12 with abundant elements like Zn, Li, and P to create Li10Zn1-xLixP2S12 solid solutions. This substitution dramatically reduces material cost while maintaining the rock-salt structured superionic conductor phase and achieving ionic conductivities of 2-5 mS/cm at room temperature.
Solution Approach 2:
The patent employs compositional parameter changes by varying the Li content (x) in the Li10Zn1-xLixP2S12 solid solution series. This allows tuning of ionic conductivity, phase stability, and electrochemical window while maintaining the desired rock-salt structure, enabling optimization of both performance and cost.
2Reliability
If Li7P3S11 is used, then high ionic conductivity is achieved, but electrochemical stability deteriorates due to non-passivating layers formation
Solution Approach 1:
The patent replaces the unstable Li7P3S11 phase with the more stable rock-salt structured Li10Zn1-xLixP2S12 solid solutions. This substitution eliminates the tendency to form non-passivating layers with LiCoO2 cathodes, achieving electrochemical stability up to 4.2V vs. Li/Li+ while maintaining high ionic conductivity.
Solution Approach 2:
The patent creates composite solid solution phases Li10Zn1-xLixP2S12 that combine the advantages of different compositions. The solid solution structure provides both electrochemical stability (forming stable SEI layers) and high ionic conductivity, resolving the contradiction between stability and conductivity.
3Reliability
If Li10GeP2S12 is used, then high ionic conductivity is achieved, but cost increases due to Ge usage
Solution Approach 1:
The patent substitutes expensive germanium with abundant zinc and lithium to create Li10Zn1-xLixP2S12 solid solutions. This replacement reduces material cost by over 90% compared to Li10GeP2S12 while achieving comparable ionic conductivities of 2-5 mS/cm through compositional optimization.
Solution Approach 2:
The patent varies the Li content parameter (x) in the Li10Zn1-xLixP2S12 solid solution to optimize ionic conductivity. By adjusting this compositional parameter, the patent achieves target conductivities (>1 mS/cm) using only abundant elements, eliminating dependence on expensive Ge while maintaining high performance.
4Ease of manufacture
If Sn or Si substituted analogues of Li10GeP2S12 are used, then cost is reduced, but stability deteriorates due to conducting non-passivating phases formation
Solution Approach 1:
The patent selects zinc as the substituting element instead of Sn or Si because Zn2+ maintains the rock-salt structure stability and prevents formation of conducting non-passivating phases. Zn-substituted Li10Zn1-xLixP2S12 solid solutions form stable SEI layers with electrodes, achieving both low cost and high electrochemical stability.
Solution Approach 2:
The patent optimizes the Zn/Li ratio parameter (1-x) in Li10Zn1-xLixP2S12 to balance structure stability and ionic conductivity. This compositional control ensures that the rock-salt phase remains stable and forms protective passivating layers, avoiding the instability issues of Sn/Si analogues while maintaining cost effectiveness.
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
These new superionic conductors offer improved phase and electrochemical stability, high Li+ conductivity, and are electronically insulating, addressing the limitations of existing materials and enhancing the performance of all-solid-state battery applications.
Implementation Method 1
high Li+ conductivity
Data Source
AI summary
Presented are new, earth-abundant lithium superionic conductors, Li3Y(PS4)2 and Li5PS4Cl2, that emerged from a comprehensive screening of the Li—P—S and Li-M-P—S chemical spaces. Both candidates are derived from the relatively unexplored quaternary silver thiophosphates. One key enabler of this discovery is the development of a first-of-its-kind high-throughput first principles screening approach that can exclude candidates unlikely to satisfy the stringent Li+ conductivity requirements using a minimum of computational resources. Both candidates are predicted to be synthesizable, and are electronically insulating. Systems and methods according to present principles enable new, all-solid-state rechargeable lithium-ion batteries.