# US 9,518,335 B2 · Method of fabricating improved porous metallic material and resulting structure thereof

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- Number: US 9,518,335 B2
- Document ID: US9518335B2
- Status: Granted
- Kind: B2
- Application number: 14/146,072
- Filed: 2014-01-02
- Published: 2015-07-02
- Granted: 2016-12-13
- Earliest claimed: 2014-01-02
- Assignees: City University of Hong Kong
- Applicants: City University of Hong Kong
- Inventors: Jie Zhang; Yang Yang Li; Jian Lu
- Web page: https://patentgrep.com/patent/US9518335B2

## CPC

- C25F 3/14: locally
- C23F 1/00: Etching metallic material by chemical means (manufacture of printing surfaces B41C; manufacture of printed circuits H05K)
- C25F 3/02: Etching
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25

## Abstract

A porous metallic material for making a structure is fabricated by subjecting the material structure to Surface Mechanical Attrition Treatment (SMAT) once, using the SMAT-treated structure as an electrode, and selectively etching away at least one metal component in the SMAT-treated structure once, thus forming an etched-away structure. Additional SMAT treatment and/or etching treatment to the etched away structure may be performed. The resulting structure has improved physical characteristics.

## Claims

### Claim 1

A method of manufacture of an electrode having a porous metallic material and a coating of varying thickness on the porous material, comprising sequential steps of:
i) providing, by way of melting, a structure made of an alloy system with at least a first metal component of Cu or Zn and a second metal component selected from the group consisting of Au, Ag, Pt and Cu, wherein the first metal component is more reactive than the second metal component;
ii) subjecting the structure to Surface Mechanical Attrition Treatment (SMAT) for duration varying from 30 seconds to 12 minutes, forming a first SMAT-treated structure;
iii) selectively etching away the more reactive first metal component in the SMAT-treated structure by immersion in an electrolyte of hydrochloric acid with or without a voltage field applied, thus forming a first etched away or fabricated porous structure of Au, Ag, Pt or Cu; and
iv) electrochemically depositing electroactive material onto the fabricated porous Au, Ag, Pt or Cu with varied deposition amount.

### Claim 2 (depends on 1)

A method as claimed in claim 1, comprising a step, after step by using the first SMAT-treated structure as an electrode substrate.

### Claim 3 (depends on 1)

A method as claimed in claim 1, the etched structure is coated with electroactive material, as a final structure for supercapacitor electrode.

### Claim 4 (depends on 1)

A method as claimed in claim 1, wherein the alloy system consists of the first metal component and the second metal component.

### Claim 5 (depends on 1)

A method as claimed in claim 1, wherein, after step iii), including a step of treating the etched away structure by applying a photocatalytic coating thereon.

### Claim 6 (depends on 1)

A method as claimed in claim 1, wherein, after step iii), including a step of attaching chemical species to surface of the etched away structure.

### Claim 7 (depends on 6)

A method as claimed in claim 6, wherein the chemical species is metal oxides.

### Claim 8 (depends on 1)

A method as claimed in claim 1, wherein the first metal component and the second metal component are Zn and Cu, respectively.

### Claim 9 (depends on 1)

A method as claimed in claim 1, comprising, in step iii), separating the etched away structure and using the etched away and separated structure as a free standing film.