Insertion of bi-valence cations Mg2+ and Zn2+ into V2O5

~

Solid State Communications, Printed in Great Britain.

Vol.61,No.5,

pp.27]-273,

1987.

0038-|098/87 $3.00 + .00 ~ 1 9 8 7 Pergamon Journals Ltd.

INSERTION OF ~I-VALENCE CATIONS Mg2~ AND Zn 2+ INTC V205 Wen-hal Yu, Da-zhi Wang, Bin Zhu*, Shen-jun Wang and Li-xin Xus (University of Science and Technology of China, ~efei, Anhui, China) (Received 26 September

1986 by W.Y. Kuan)

ABSTRACT: The fresh cross sections of the interface between Mg- or Zn-montmorillonite as a solid electrolyte and V205 as a cathode in MgtV205

or ZnIV205 cell have been investigated

by SEM and EMP.

It

is shown that the bi-valence cations Mg 2÷ and Zn 2+ also can be inserted into V205 and give a conclusive evidence on migration of ~g2+ and Zn 2+.

A number of cathode materials

works on insertion of single-valence cathode materials

such as TiS 2,

interface between Mg- or Zn-montmoriIlonite

for rechargeable

solid batteries have been investigated

and many

cations into

observed

V205, V}O8, V6015

on scanning electron microscope

well as electron microprobe microscope.

etc. have been reported 1'2. Recently,

(EMP) by X-650 electron

Photo I is the SEM image for cell A before dis-

we have found that the bi-valence

V205.

It has been reported that montmorillonite,

which

is provided with a better ionic exchangeability conductivity,

and

can be used in solid state batteries

as a solid electrolyte 3 .

Ng- and Zn-montmoril]onite

have been used to assembly two kinds of solid cells as following: A.

Mg t Mg-montmorillonite

p V205

B.

Zn P Zn-montmorillonite

p V205

The p±operties

of charge and discharge for these

cells are very good as shown in Table I. To investigate whether Mg 2+ and Zn 2+ might be inserted

into V205,

the fresh cross section of the

Table I.

Cell

properties of discharge average current cut off capacity (~A) volta6e (V) (mAh)

cell area (gm 2)

(A)

1.5

26

1.0

8.0

1.55

(B)

1.1

28

0.9

5.7

1.53

voltage (V)

*University

Fig. 1

Properties of charge and discharge for (A) MgPV205 and (B) Zn'V20 ~ cells

average voltage (V)

cyclic properties of charge-discharge current (~A) deep of charge-discharge charge-discharge

1.5

50

2o %

1.2

50

10 %

of Science and Technology

(SEM) as

The results are shown in Photo I to 4.

cations Mg 2+ and Zn 2+ also can be inserted into the cathode

and

V205 in these cells before and after discharge were

15 25

of Staffs and Workers of Hefei 271

cycles

272

INSERTION OF FI-VALENCE CATIONS Mg2+AND Zn 2+ INTO V205

Vol. 61, No. 5

charge, the left is V205 and the right is Mg-montmorillonite.

The EMP analysis on Mg content has

been carried out along line AA'

It is found that

the distribution of Mg content displays a jump at the interface.

In the side of V205, Mg content is

approximatly zero, and on other side of Mg-montmorillonite,

it shows a maximum near the interface

and decrease gradually with the increasing of the distance from the interface. Photo 2 is the result of EMP analysis on Mg con-

Fig. 3

Fig. 2

tent for cell A after discharge.

It is apparent

that magnesium has gone far into V205 and its content decrease with the increasing of the distance from the interface.

Fig. 4

The EMP analysis on V and Si

content also has been carried out along same line. It is obvious that the distribution of Si, which is the characteristic

element of montmoriilonite,

and

Table 2 shows the results of XRD analysis for V205 before and after discharge.

It is

that of V, which is the characteristic element of

exhibited that the lattice has been expanded

V205, are provided with the relation of complement

because of the insertion of Mg and Zn into

each other.

V205 •

Then the interface is shown clearIy

therefrom.

By above-mentioned

Photos 3 and 4 are the results of EMP analysis for cell B before and after discharge, PB' is

inltia] results, it is

shown that V205 also can be inserted by bivalence cations Mg 2+ and Zn 2+ and form some

scanning lime, and the results are slmiffar to

inserted compounds.

that from Photos I and 2.

the insertion of Li + cation into V20~4.

Table 2.

This is similar to that

Change of the eharactiristic interplanar distance in V205 before and after discharge hkl

200

001

110

011

400

002

5.758

4.372

3.403

2.762

2.880

2.184

d (after inserting of Mg)

5.784

4.~84

3.422

2.768

2.886

2.187

d (after inserting of Zm)

5.825

4.409

3.422

2.777

2.896

d (before discharge)

Vo[. 6], No. 5

INSERTION OF ~I-VALENCE

CATIONS Mg2+AND Zn 2+ INTO V205

273

References:

I.

D. W. Murphy, Solid State lonics 18 & 19 (I 986), 847.

2.

5.

Publishing, 4.

io68.

Da-zhi Wang et al, in " Materials for Solid State Batteries

1986 " ed. by B. V. R.

Chowdar± and S. Radhakrishna,

R. Kanno et al, Solid State Ionics 18 & 19 (1986),

Workshop, Singapore,

-- Proceedings

of the Regional

Singapore,

World Scientific

1986, p. 461.

B. Monisha, Solid State Ionics 18 & 19 (1986),

902.