Crystalline Li1+xAlxTi2−x(PO4)3 Electrolyte for 3D Microbatteries

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Solution Overview

Problem

Conventional lithium-based solid-state batteries face challenges due to low ionic conductivity in their thin-film electrolytes, such as LiPON, which limits their performance in terms of power density, energy density, and cycle lifetimes.

Innovation Solution

A solid-state rechargeable 3D microbattery is developed using a crystalline Li1+xAlxTi2−x(PO4)3 electrolyte, which offers higher ionic conductivity and chemical stability, enabling improved power density, energy density, and extended cycle lifetimes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional LiPON thin-film electrolyte is used, then the battery structure is simple and easy to manufacture, but the ionic conductivity is low (10^-5 to 10^-6 S/cm)

Engineering Contradiction:

Improveionic conductivityVSAvoidelectrolyte material complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by substituting Ti and P with Al in controlled ratios (x=0.1 to 1.0), transforming the material from conventional LiPON to Li1+xAlxTi2-x(PO4)3. This compositional parameter change increases ionic conductivity from 10^-5 to 10^-6 S/cm to greater than 10^-4 S/cm while maintaining the thin-film structure and manufacturability through sputtering deposition.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte material Li1+xAlxTi2-x(PO4)3 by combining multiple elements (Li, Al, Ti, P, O) in specific ratios. This composite approach leverages the beneficial properties of each element: Li for ionic conductivity, Al for structural stability and conductivity enhancement, Ti for structural framework, and P for chemical stability, achieving superior overall performance compared to single-component LiPON.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If battery capacity is increased to power portable devices longer, then energy storage is sufficient, but the power supply becomes heavy and large

Engineering Contradiction:

Improveenergy storage capacityVSAvoidpower supply weight

Core Design Contradiction:

Quantity of substanceVSWeight of moving object

Solution Approach 1:

The patent changes the ionic conductivity parameter of the electrolyte by factor of 10-100 times through compositional modification, enabling higher current densities and faster charge/discharge rates. This allows the battery to achieve the same power output with smaller electrode areas and less active material, reducing overall battery weight and volume while maintaining sufficient energy storage capacity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent transitions from conventional planar (2D) battery architecture to a three-dimensional stacked microbattery structure with multiple layers of electrodes and electrolytes. This dimensional change increases the effective surface area for electrochemical reactions without proportionally increasing the footprint, enabling higher energy density in a compact, lightweight form factor suitable for portable devices.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If LiPON electrolyte is used, then the manufacturing process is simple, but the power density and energy density are limited

Engineering Contradiction:

Improvepower densityVSAvoidcycle lifetime

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent optimizes the compositional parameters of the electrolyte (specifically the Al substitution ratio x) to achieve peak ionic conductivity and chemical stability. The optimized composition Li1+xAlxTi2-x(PO4)3 with x=0.1 to 1.0 provides both high power density through enhanced ionic transport and extended cycle lifetime through improved chemical stability, simultaneously addressing both performance requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional LiPON electrolyte layer with a new crystalline electrolyte material Li1+xAlxTi2-x(PO4)3 that exhibits superior ionic conductivity and chemical stability. This material substitution enables the battery to achieve higher power density through faster ion transport and extended cycle lifetime through reduced degradation, while maintaining compatibility with existing sputtering manufacturing processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 crystalline Li1+xAlxTi2−x(PO4)3 electrolyte provides ionic conductivity greater than 10−4 Siemens/cm, enhancing the performance of solid-state rechargeable batteries by increasing their power density, energy density, and cycle lifetimes compared to conventional LiPON-based batteries.

Implementation Method 1

a layer of crystalline Li1+xAlxTi2−x(PO4)3 is sputtered using the pellets as a solid-electrolyte source

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS10749199B2Li1+xAlxTi2-x(PO4)3 solid-state thin film electrolyte for 3D microbattery and method of fabrication

Publication Date: 2020.08.18 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A solid-state rechargeable 3D microbattery is provided that has improved power density, energy density, and cycle lifetimes. These improvements are afforded by providing a solid-state electrolyte that is composed of crystalline Li1+xAlxTi2−x(PO4)3, wherein x is from 0 to 2. The solid-state electrolyte that is composed of crystalline Li1+xAlxTi2−x(PO4) has a high ionic conductivity (which is greater than 10−4 Siemens/cm) as well as high chemical stability.