BU-217: Summary Table of Alternate Batteries

Our lexicons list weird and wonderful batteries, but as with animal species, not all become house pets.  A battery has stringent requirements. No less than eight requirements must be met to call a battery a battery. (See BU-104c: The Octagon Battery.)  Table 1 summarizes the less common batteries that serve various niche markets.


Sodium-sulfur; Sodium-nickel-chloride (ZEBRA)

(Primary and secondary)


Reusable Alkaline


Molten-salt (Na) and sulfur (S). Economical with larger sizes, (Symbol NaS)

Mainly primary; shares similarity with fuel cell

Silver-zinc is rechargeable; silver-oxide is primary

Disposable alkaline made reusable at a similar cost to regular types

Voltage per cell





Specific Energy




200Wh/kg, less with each subsequent recharge


Operate at

Removal of seal enables airflow




Overnight charge

Charging by replacement of zinc electrodes

Similar to Li-ion

Voltage limiting


High power burst

Low load

Similar to Li-ion

Low load (200–400mA)

Cycle life

3,000 cycles;
8 years

Once activated, battery is being consumed

Short cycle life;
2 year life span

50, depending on DoD. Recharge often


Keep battery hot

Only activate when needed

Keep inventory low

Do not discharge too low

Failure modes

Electrical shorts due to corrosion

Sensitive to cold heat, humidity and air pollution

Zinc electrode and separator decay; cycling causes dendrite formation

50% capacity drop with 2nd charge; rising internal resistance


Large systems of 10kWh and higher

Mostly small sizes

Button cells (silver-zinc)

AA, AAA, C, D, 9V


Conceived by Germans in World War II; NaS gained new interest in 1970s

“Breathing” discovered by Leclanché in 1878, offered to buyers in 1932

Spacecraft use because of high capacity. (Now replaced by Li-ion)

Introduced in 1992, alternate to disposables. Leak-proof


Primary: One-shot missiles; Secondary: UPS, load- leveling, EV (Think City), delivery vans

Hearing aids; large units for railway signaling, mines safety lamps

Primary: Watches, memory backup; Secondary: Aerospace, missiles, military, TV cameras

Flashlights, toys, entertainment devices


Heating consumes 14% of battery energy per day

High capacity, low cost but only one-time use

New designs show capacity gain over Li-ion: expensive raw material

Regular alkaline should not be charged; danger of leakage, gas, explosion

Table 1: Summary of most common alternative batteries and equivalent. Detailed information is on BU-211: Alternate Battery Systems. All readings are estimated and may vary with different versions and newer developments.

Table 2 touches on semi-batteries. They are listed because of similarities with the electrochemical reaction of a real battery. What was once a unique device standing on its own is now merging with the battery, and the supercapacitor is such an example. The fuel cell has similarities also in that it is a battery in reverse. Overcharging a battery turns water into hydrogens and oxygen (gassing); the fuel cell produces electricity and water by combining hydrogens and oxygen.



Flow Battery

Fuel Cell


Double-layer capacitor. Stores energy by static charge as opposed to electrochemical reaction

Rechargeable; pump operated, electrolyte stored in tank

Combining hydrogen and oxygen produces electricity

Voltage per cell

Limited at 2.30–2.75V



Specific Energy

5Wh/kg (typical)





sluggish ramp-up

sluggish ramp-up


1–10s; simple charging, current stops when full

Overnight charge

Hydrogen feed through tank


Very high power

Low load current

Low load current

Cycle life

1 million; 10–15 years

10,000 cycles; 20 years.

2,000–4,000h; stationary up to 40,000 hours


Low maintenance



Failure modes

Exceeding voltage limits lowers service life

High corrosion. Vanadium keeps corrosion under control

Stack damages by freezing and heat; capacity fade by cycling.


Mostly in cylindrical formats

Large systems; 20kWh and up

Large, also portable


Broad temperature range. Non-toxic.

Functions more like a refinery than a battery

Must have correct moisture content. Cannot freeze.


GE experimented in 1956; Standard Oil discovered double layer in 1966; NEC commercialized it in 1978

First patent in 1954. Current types patented in 1986

William Grove, developed in 1839; space program 1960s


Memory backup, generator start, large MW systems. In competition with flywheel

Large energy storage system; economical with large size

Forklift, EV, UPS, portable usage in military


Expensive per Wh. Some argue to spend the money on a larger battery

Capacity set by tank size; can be enlarged if so needed

Clean but expensive; poor power band

Table 2: Summary of most batteries that deviate from the electro-chemical concept of a battery. Readings are estimated and may vary with different versions and newer developments. All readings are estimated average at time of publication. Detailed information is on:
BU-209: How does a Supercapacitor Work?
BU-210b: How does the Flow Battery work?
BU-210: How does the Fuel Cell Work?

Last updated 2016-07-19


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Comments (2)

On December 29, 2016 at 5:19am
Noel Jealous wrote:

Alternate means to flip between two states. My rubbish is collected on alternate Thursdays.
I think you mean Alternative.

On March 9, 2017 at 10:20am
Rog wrote:

Really Noel? These folks provide a comprehensive if not the most detailed education in one spot and the best you can do is play semantics? Most readers I’m sure, appreciate the highly valued information that is provided here for us!

Shame on you!