Solid-State Lithium Battery Using Black Phosphorus Cathode
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Solution Overview
Problem
Lithium/iodine cells, despite their reliability and long life, operate at low power and high impedance due to low ionic and electronic conductivity, which limits their energy density and practical application in high-demand devices.
Innovation Solution
A solid-state lithium battery composition featuring a lithium-containing anode and a phosphorus-containing cathode, specifically using black phosphorus, which is electronically conductive and reacts to form a lithium-ion conducting electrolyte (lithium phosphide) in-situ, eliminating the need for a pre-existing separator and enhancing conductivity and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium/iodine cells use solid electrolyte generated in-situ, then reliability and storage stability are improved, but power output and ionic conductivity deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by replacing iodine with phosphorus and adding specific additives (Bi2O3, PbO, B2O3) to modify the electrolyte's ionic conductivity and electrochemical properties, thereby improving power output while maintaining reliability
Solution Approach 2:
The patent creates a composite solid electrolyte system combining lithium phosphide with metal oxides (Bi2O3, PbO, B2O3) to achieve synergistic effects that simultaneously improve ionic conductivity, electrochemical stability, and power output while maintaining the self-healing reliability of in-situ formed electrolytes
2Stability of the object's composition
If lithium/iodine cells use solid electrolyte, then storage stability and resistance to shock are improved, but energy density deteriorates due to low ionic conductivity
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating phosphorus-based compounds and metal oxide additives to enhance ionic conductivity, which directly increases the effective quantity of active material and improves energy density while preserving storage stability
3Power
If black phosphorus cathode is used, then electronic conductivity and energy density are improved, but cell complexity increases due to in-situ electrolyte formation mechanism
Solution Approach 1:
The patent employs self-service by designing the cell to automatically form its own electrolyte through the chemical reaction between lithium anode and phosphorus-containing cathode materials during initial charging, eliminating the need for separate electrolyte application steps and reducing overall cell complexity despite the sophisticated in-situ formation mechanism
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
The lithium/phosphorus battery achieves higher energy density and power output than lithium/iodine cells, with the in-situ formed lithium phosphide electrolyte ensuring reliable operation and preventing short circuits, making it suitable for powering electronic devices with improved performance.
Implementation Method 1
the reaction between the anode and cathode itself generates the solid electrolyte phase, lithium iodide (LiI)
Implementation Method 2
Solid electrolytes for lithium cells must be both lithium ion conducting and electronically insulating
Implementation Method 3
The electrolyte propagates through the active materials as the cell is discharged and more reaction product or electrolyte is formed
Data Source
AI summary
A solid-state lithium battery including a lithium-containing anode and a phosphorus-containing cathode is disclosed. The cathode may include any of a number of electronically conductive allotropes of phosphorus, referred to as a group as black phosphorus. A solid discharge product of the cell acts as an electrolyte for the cell. The cathode may include an auxiliary electronic conductor phase to improve the conductivity of the cathode, improve the cathode utilization during discharge and reduce the overall cell impedance.