# US 2013/0280609 A1 · Alloys Of Clathrate Allotropes For Rechargeable Batteries

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- Number: US 2013/0280609 A1
- Document ID: US20130280609A1
- Status: Published application
- Kind: A1
- Application number: 13/452,403
- Filed: 2012-04-20
- Published: 2013-10-24
- Earliest claimed: 2012-04-20
- Assignees: Southwest Research Institute
- Inventors: Candace K. CHAN; Michael A. MILLER; Kwai S. CHAN
- Web page: https://patentgrep.com/patent/US20130280609A1

## CPC

- H01M 4/134: Electrodes based on metals, Si or alloys
- C01B 33/00: Silicon; Compounds thereof ({C01B6/00,} C01B21/00, C01B23/00 take precedence; persilicates C01B15/14; carbides C01B32/956)
- C22C 1/00: Making non-ferrous alloys (by electrothermic methods C22B4/00; by electrolysis C25C1/24, C25C3/36)
- H01M 4/38: of elements or alloys
- H01M 4/386: {Silicon or alloys based on silicon}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present disclosure is directed at an electrode for a battery wherein the electrode comprises clathrate alloys of silicon, germanium or tin. In method form, the present disclosure is directed at methods of forming clathrate alloys of silicon, germanium or tin which methods lead to the formation of empty cage structures suitable for use as electrodes in rechargeable type batteries.

## Claims

### Claim 1

An electrode for a battery wherein said electrode comprises clathrate alloys of silicon, germanium and/or tin.

### Claim 2 (depends on 1)

The electrode of claim 1 wherein said alloy comprises particles having a largest linear dimension of in the range of 0.1 μm to 100.0 μm.

### Claim 3 (depends on 1)

The electrode of claim 1 wherein said electrode comprises a metal substrate and said clathrate alloy is present on the surface of said metal substrate.

### Claim 4 (depends on 1)

The electrode of claim 1 wherein lithiation of said alloy results in a volume expansion of less than or equal to 50.0%.

### Claim 5 (depends on 1)

The electrode of claim 1 wherein said electrode comprises an anode electrode in a Li battery.

### Claim 6 (depends on 1)

The electrode of claim 1 wherein said electrode comprises a cathode electrode in a Li battery.

### Claim 7 (depends on 1)

The electrode of claim 1 comprising a Type I clathrate alloy containing an arrangement of 20-atom and 24-atom cages fused together through 5 atom pentagonal rings.

### Claim 8 (depends on 7)

The electrode of claim 7 wherein said Type I clathrate alloy has the formula:
AxMyX46-y
where A=Li with none, one or more guest atoms from group 1A, group 2A, group 1B, group 2B, group 3B, group 5A, group 7A and group 8; M=B, Al, P, S, Cu, Ni, Zn, Ag, Au, Pt, Ga, Se or any metal or metalloid element capable of forming a clathrate with X wherein X=Si, Ge and/or Sn and M≠X≠A and y is an integer, a fraction or a number plus a fractional part.

### Claim 9 (depends on 8)

The electrode of claim 8 wherein said metals comprise alkali metals, alkaline earth metals, transition metals, post-transition metals, lanthanides or actinides.

### Claim 10 (depends on 8)

The electrode of claim 8 wherein said metalloids comprise silicon, germanium, or tin.

### Claim 11 (depends on 1)

The electrode of claim 1 comprising a Type II clathrate alloy containing an arrangement of 20-atom and 28-atom cages fused together through 5 atom pentagonal rings.

### Claim 12 (depends on 1)

The electrode of claim 1 wherein said Type II clathrate alloy has the formula:
AxMyX34-y
where A=Li with none, one or more guest atoms from group 1A, group 2A, group 1B, group 2B, group 3B, group 5A, group 7A and group 8; M=B, Al, P, S, Cu, Ni, Zn, Ag, Au, Pt, Ga, Se or any metal or metalloid element capable of forming a clathrate with X wherein X=Si, Ge and/or Sn and M≠X≠A and y is an integer, a fraction or a number plus a fractional part.

### Claim 13 (depends on 12)

The electrode of claim 12 wherein said metals comprise alkali metals, alkaline earth metals, transition metals, post-transition metals, lanthanides or actinides.

### Claim 14 (depends on 12)

The electrode of claim 12 wherein said metalloids comprise silicon, germanium or tin.

### Claim 15

A lithium-ion battery comprising an anode containing clathrate alloys of silicon, germanium and/or tin, a cathode and an electrolyte.

### Claim 16

A method of forming Type I empty clathrate of silicon, germanium or tin, or alloy thereof, comprising the following scheme:
n[R′—CH2—NR3]+Z−+[X′xX″y-x]n−→y[X′xX″46-x]0[Clathrate I]+n[R′═CH2]+nNR3+n/2H2
R′=—(CH2)n—CH3;
R3=—CH3, H;
X′ or X″=Si, Ge, or Sn, and X′≠X″;
Z=halogen or any other negatively charged counter-ion;
y in [X′xX″y-x]n− and in y[X′xX″46-x]0=a number corresponding to a stable cluster size;
n in [X′xX″y-x]n−=the formal charge of a stable cluster anion that depends on n, the starting number of moles of an alkyl ammonium salt;
n in n[R′—CH2—NR3]+Z−=the starting number of moles of an alkyl ammonium salt;
wherein R′ comprises any alkyl and/or branched alkyl and the value of n in R′=(CH2)n—CH3 is 1-50 and R′ when bonded to the indicated methylene group proceeds through a methine (—CH═) type linkage;
and incorporating the following steps:
(a) preparing an ionic liquid consisting of dodecyltrimethylammonium cation (DTMAC) and bis(trifluoromethylsulfonyl)imide anion (BTFMSI);
(b) combining the said DTMAC-BTFMSI ionic liquid with alkali- or alkaline earth compounds of the metalloids Q(X′xX″2-x) or Q4(X′xX″9-x), where Q=Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, and Ra; and X′ or X″=Si, Ge, Sn, and X′≠X″, where x is an integer, a fraction, or a number plus a fractional part, to form the charged cluster [X′xX″y-x]n−;
(c) in the absence of air or moisture, heating a reaction mixture of n[R′—CH2—NR3]+Z−+[X′xX″y-x]n−;
(d) forming the Type I empty clathrate of the form [X′xX″46-x]0; x=0 to 46;
(e) isolating the Type I empty clathrate product from the remaining liquid reaction mixture.

### Claim 17 (depends on 16)

The method of claim 16 further comprising forming an electrode from the Type I empty clathrate and electrochemically intercalcating the guest sites of such electrode material with lithium.

### Claim 18 (depends on 17)

The method of claim 17 further comprising positioning said lithium intercalcated clathrate electrode in a battery.