Lithium-Iodine Batteries

Iodine — Iodine, L, is a halogen which occurs naturally mainly as iodide, I- [i]. Iodine (Greek ioeides for colored violet ) is a black solid with a melting point of 113.6 °C which is readily undergoing sublimation to form a violet gas. Iodine occurs in the oxidation states -1,0, +1, +3, +5, +7 and it possesses a rich redox chemistry [ii]. In aqueous solution the formation of I2 from I- occurs with a standard potential of 0.621V vs. SHE and this oxidation process is preceded by the formation of I3 with a standard potential of 0.536 V vs. SHE. For the reaction I2(cryst) + 2e - 21 E = 0.535 V. The I—/I3 redox couple is employed, for example, in solar cells [iii] and in long-lived lithium-iodine battery systems. The oxidation of I2 in organic solvents results formally in I+ intermediates which is a powerful oxidant and useful, for example, in electro-synthetic chemical processes [ii]. 

Schmidt CL, Skarstad PM (1997) Development of an equivalent-circuit model for the lithium/iodine battery. J Power Sources 65 121-128... 

A dry cell is not truly dry, because the electrolyte is an aqueous paste. Solid-state batteries have been developed, however. One of these is a lithium-iodine battery, a voltaic cell in which the anode is lithium metal and the cathode is an I2 complex. These solid-state electrodes are separated by a thin crystalline layer of lithium iodide (Figure 20.11). Current is carried through the crystal by diffusion of Li" ions. Although the cell has high resistance and therefore low current, the battery is very reliable and is used to power heart pacemakers. The battery is implanted within the patient s chest and lasts about ten years before it has to be replaced. 

Nernst equation (20.7) zinc-carbon (Leclanche) dry cell (20.8) alkaline dry cell (20.8) lithium-iodine battery (20.8) lead storage cell (20.8) nickel-cadmium cell (20.8)... 

Lithium-iodine battery a voltaic cell in which the anode is lithium metal and the cathode is an I2 complex. (20.8)... 

Lithium iodine batteries are available mostly in the pacemaker shape, i.e. in that flat nearly semicircle geometry of, e.g. 5 x 30 x 40 mm, with 1 to 3 Ah capacity at a weight of 10 to 30 g. For industrial applications flat rectangular formats are made with contact pins that make them mountable onto electronic boards. Button cells are also realizable. All cells have glass-to-metal seals for both polarities or for the negative one only. A button cell s cross-section is shown in Figure 18.26... 

C. L. Schmidt and P. M. Skarstad, Development of a Physically-Based Model for the lithium/ Iodine Battery, in T. Keily and B. W. Baxter (eds.), Power Sources, vol. 13, International Power Sources Committee, Leatherhead, England, 1991, pp. 347-361. 

Zhao Y, Wang L, Byon HR (2013) High-performance rechargeable lithium-iodine batteries using triiodide/iodide redox couples in an aqueous cathode. Nat Commun 4 1896... 

The lithium-iodine battery has been used to power more than 3.5 million cardiac pacemakers since its introduction in 1972. During this time the lithirrm-iodine system has established a record of reliability and performance unsurpassed by any other electrochemical power source. 

The lithium-iodine battery has a solid anode of lithium and a polyphase cathode of poly-2-vitiyl-pyridine (P2VP), which is largely iodine (at 90% by weight). The solid electrolyte is constituted by a thin film of Lil. The discharge reaction is given by... 

In the case of pacemaker, power delivery is not a problem because the device itself is of low power consumption and lithium iodine batteries can support a... 

Hi redox couple is employed, for example, in solar cells [iii] and in long-lived lithium-iodine battery systems. The oxidation of I2 in organic solvents results formally in H intermediates which is a powerful oxidant and useful, for example, in electro-synthetic chemical processes [iij. 

Beginning in 1968, the implantable prototypes of fuel cells intended to power a pacemaker were developed by the American Hospital Supply Corporation [6], the Michael Reese Hospital [8], Siemens [13], and Tyco [14]. Industries also invested in the organochemical redox systems in order to develop devices that are able to oxidize not only glucose but also other fuels, such as amino acids [15]. However, the introduction of lithium iodine batteries as a power supply for pacemakers, and the improvement in its lifetime, led to a change in the direction of the application of glucose/02 fuel cells toward sensor technology [16,17]. 

Since 1972, the Catalyst Researeh Corporation (USA) has been the supplier of the lithium-iodine batteries intended initially for eardiae paeemakers and other implantable deviees. They supply 70% of pacemaker batteries used in the world. They elaim that the capacity of this battery is four times that of the Mallory RM-I mereury-zine paeemaker battery and that the lithium-iodine battery operates more efficiently at body temperature than at room temperature. Since the lithium-iodine reaetion generates no gas, the cell can be hermetieally sealed. A feature of this type of battery is its extremely high reliability. At the time of writing, Catalyst Researeh had supplied 150000 batteries for use in eardiae paeemakers without a single failure or premature rundown. Catalyst Researeh Corporation lithium-iodine batteries are marketed in the UK by Mine Safety Appliances Ltd. 

The lithium-iodine battery differs from other lithium batteries in the following respeets ... 

Lithium-iodine batteries eontain no liquid electrolyte. 

Lithium-iodine batteries do not require a separator material to keep the anode from eontaeting the cathode. 

Catalyst Research Corporation (USA) is a major manufacturer of lithium—iodine batteries used for pacemaker and other applications. The Catalyst Research Series 800 cells use the lithium envelope concept. The cell is constructed with a centrally located cathode current collector and a lithium envelope which surrounds and contains the iodine depolarizer material (Figure 24.14). This depolarizer material is corrosive to the stainless steel case and must be kept irxnn contacting the case for maximum cell life. A second barrier, formed from fluorocarbon plastics, surrounds the lithium envelope, insulates it from the case, and provides a second envelope for the containment of the depolarizer. The corrosive effect of iodine-containing depolarizer on stainless steel is lower than that of depolarizer made with more active halogens, such as bromine or chlorine. 

Lithium-iodine batteries in the 35-lOOOmAh capacity range are available for printed circuit board applications. 

One currently available lithium system, which seems to meet most of the requirements for an ideal CMOS-RAM back-up power source, is the lithium-iodine battery. The lithium-iodine battery has long life characteristics, and is designed for wave soldering and printed circuit board mounting. 

When current is not being drawn from a lithium-iodine battery, as is often the case in memory back-up applications, self-discharge takes plaee. Selfdischarge is a natural process which consumes aetive battery materials and, hence, battery capacity. Capacity losses at 25°C vary from less than 5%over 10 years for lithium-iodine batteries to more than 25% per month for some secondary batteries. 

An advantage of the lithium—iodine battery is its temperature performance. Not only does the battery operate over a wide temperature range (—55 to -t-125°C), but it has a high impedance at low temperatures and low impedance at high temperatures. Therefore, as the power requirements of the memory chip decrease with a decrease in temperature, the lithium—iodine battery reacts similarly by providing less cunent to the chip and vice versa. 

Lithium-iodine batteries 56/19 Table 56.21 Duracell solid electrolyte batteries... 

Since 1972, Catalyst Research Corporation has been the supplier of lithium-iodine batteries for cardiac pacemakers and other medical implantable devices and, more recently, for other applications of these batteries. 

The 900 Series Lithiode lithium-iodine implantable medical cell manufactured by Catalyst Research represents the latest innovation in lithium-iodine batteries. The innovation is in the cell s internal construction. Instead of using a cooked-and-cast cathode, as employed in the earlier 700 and 800 series of Catalyst Research lithium-iodine cells, the 900 series utilizes a unique pelletized cathode. 

---