Solid-State Battery Electrode Pairing for Energy Density and Safety
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Solution Overview
Problem
Current all-solid-state batteries face challenges in achieving high energy density while ensuring safety and stability, particularly in selecting suitable cathode and anode active materials that balance potential differences and safety considerations.
Innovation Solution
The development of an all-solid-state battery using a cathode active material represented by the chemical formula Li2Fe(1-x)MxP(2-y)AyO7, where M includes metals like Ti, V, Cr, Ni, and Co, and A includes elements such as B, C, Al, Si, and Ge, combined with an anatase titanium oxide anode active material, to enhance energy density and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional lithium secondary batteries use flammable organic electrolyte solutions to achieve high energy density, then energy density is improved, but safety deteriorates due to leakage, short circuit, and overcharge risks
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid (flammable organic electrolyte solution) to solid (oxide-based or sulfide-based solid electrolyte), fundamentally altering the safety characteristics while maintaining ion conduction capability. This parameter change eliminates flammability and leakage issues while preserving high energy density potential.
Solution Approach 2:
The patent employs composite material structures where solid electrolytes are integrated with cathode and anode layers to form an integral sintered body. This composite approach combines the ion-conducting properties of solid electrolytes with the energy-storing capabilities of electrode materials, achieving both safety and high energy density.
2Reliability
If all-solid-state batteries use solid electrolytes to improve safety, then reliability is improved, but energy density deteriorates compared to conventional lithium secondary batteries
Solution Approach 1:
The patent optimizes parameters of solid electrolyte materials (oxide-based or sulfide-based) to enhance their ion conductivity and electrochemical stability, thereby improving the overall energy density of the all-solid-state battery while maintaining safety advantages.
Solution Approach 2:
The patent uses composite material structures integrating solid electrolytes with high-capacity cathode and anode materials, forming an integral sintered body that maximizes energy density while preserving the safety benefits of solid electrolytes.
3Use of energy by moving object
If electrode active materials with higher potential differences are selected to increase energy density, then energy density is improved, but stability deteriorates
Solution Approach 1:
The patent carefully selects and optimizes the chemical composition and electrochemical parameters of cathode and anode active materials to achieve high potential differences while maintaining compositional stability and preventing degradation during cycling.
Solution Approach 2:
The patent employs composite material structures where solid electrolytes are integrated with cathode and anode layers in an integral sintered body, creating a stable interface that maintains both high energy density and compositional stability during operation.
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 configuration achieves an energy density greater than 791 mWh/g, significantly improving charge and discharge characteristics and facilitating safer operation by optimizing the potential differences between cathode and anode layers.
Implementation Method 1
Solid electrolytes are materials mainly containing ion conductors capable of conducting ions in the solids
Implementation Method 2
a cathode layer that contains a cathode active material and a solid electrolyte, an electrolyte layer that is formed of the solid electrolyte, and an anode layer that contains an anode active material and the solid electrolyte
Data Source
AI summary
An all-solid-state battery includes an electrode body in which a cathode layer that contains a cathode active material and a solid electrolyte, an electrolyte layer that is formed of the solid electrolyte, and an anode layer that contains an anode active material and the solid electrolyte are stacked in this order in an up-down direction, in which the cathode active material is a compound represented by a chemical formula Li2Fe(1-x)MxP(2-y)AyO7, contains at least one metal of Ti, V, Cr, Ni, and Co as the M in the chemical formula, and contains at least one element of B, C, Al, Si, Ga, and Ge as the A in the chemical formula, the x in the chemical formula satisfies 0.8<x≤1, the y in the chemical formula satisfies 0≤y≤0.07, and the anode active material is an anatase titanium oxide represented by a chemical formula TiO2.