Pb-O-C Nanocomposite Anodes for Stable Lead-Based Battery Cycling
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Solution Overview
Problem
Lead-based anodes for lithium and sodium-ion batteries suffer from poor cycle stability due to large volume expansion and contraction during alloying and conversion reactions, limiting their practical application despite potential advantages of low cost and high energy density.
Innovation Solution
Development of lead/lead oxide/carbon (Pb—O—C) nanocomposites with Pb and PbOx nanoparticles encapsulated in carbon nanoparticle matrices, prepared through high-energy ball milling, which induces redox reactions and forms a PbOx@Pb shell on core nanoparticle morphology, optionally incorporating additional elements like transition metals or oxides to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lead and lead oxide electrodes are used, then low cost and high volumetric energy density are achieved, but poor cycle stability occurs due to large volume expansion and contraction
Solution Approach 1:
The patent applies the nesting principle by forming a core-shell structure where PbOx nanoparticles are encapsulated within carbon matrices. The carbon shell acts as a protective layer that contains the PbOx core, preventing volume expansion and contraction during electrochemical reactions. This nested structure resolves the contradiction by maintaining structural integrity while preserving the high energy density of lead-based materials.
Solution Approach 2:
The patent creates a composite material system combining carbon and PbOx in a nanoscale architecture. The composite structure leverages the mechanical stability of carbon to counteract the volume instability of PbOx, while maintaining the electrochemical activity of the lead oxide. This composite approach resolves the contradiction between achieving high energy density and maintaining cycle stability.
2Use of energy by moving object
If PbOx nanoparticles are used for high energy density, then volumetric energy density increases, but large volume expansion and contraction during reactions occur
Solution Approach 1:
The PbOx nanoparticles are nested within carbon matrices, creating a protective encapsulation that prevents volume expansion during electrochemical reactions. This nested structure allows the high energy density of PbOx to be maintained while the carbon shell absorbs and distributes the mechanical stress of volume changes.
Solution Approach 2:
The carbon matrix forms a flexible shell around the PbOx nanoparticles, accommodating volume changes during charge-discharge cycles. This thin film structure provides mechanical flexibility that allows the rigid PbOx core to expand and contract without structural failure, resolving the contradiction between high energy density and volume stability.
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 Pb—O—C nanocomposites demonstrate improved reversible capacity and cycle stability compared to conventional lead and lead oxide materials, making them viable for high-energy, low-cost anodes in rechargeable batteries.
Implementation Method 1
During high-energy ball milling, PbOx reacts with carbon to undergo a redox reaction producing elemental Pb and carbon dioxide
Implementation Method 2
heat-treatment at a temperature of about 30° C. to about 200° C. in air can be applied to the ball-milled product to form a PbOx passive layer on the surface of the Pb nanoparticles
Data Source
AI summary
Lead/lead oxide/carbon (“Pb—O—C”) nanocomposite materials that are useful as electrode active materials for electrodes in lithium and sodium batteries are formed by grinding a mixture of a lead oxide material and a carbon material in a high energy ball mill. A Pb—O—C nanocomposite as described herein comprises Pb and lead oxide nanoparticles homogeneously dispersed in a carbon nanoparticle matrix. In the nanocomposite, other elements (e.g., transition metals, Al, Si, P, Sn, Sb, and Bi) can be alloyed with the Pb nanoparticles, incorporated as a mixed oxide with the lead oxide nanoparticles, or can be present as distinct elemental or oxide nanoparticles within the carbon nanoparticle matrix.