chemistry

Polysulfide–bromide battery

Polysulfide–bromide battery is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Polysulfide–bromide battery rather than just read about it. In short: The polysulfide–bromine battery (PSB; sometimes polysulphide–polybromide or "bromine–sulfur") is a type of rechargeable electric battery that stores electrical energy in liquids, such as water-based solutions of two salts: sodium bromide and sodium polysulfide. It is a type of redox (reduction–oxidation) flow battery.

Key takeaways

Polysulfide–bromide battery belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Polysulfide–bromide battery to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Polysulfide–bromide battery from memory before moving on to harder problems.

Reference excerpt

The polysulfide–bromine battery (PSB; sometimes polysulphide–polybromide or "bromine–sulfur") is a type of rechargeable electric battery that stores electrical energy in liquids, such as water-based solutions of two salts: sodium bromide and sodium polysulfide. It is a type of redox (reduction–oxidation) flow battery. In 2002, a 12 MWe prototype electrical storage facility was built at Little Barford Power Station in the UK, which used polysulfide–bromide flow batteries. Although the facility was completed, due to engineering issues in scaling up the technology, it was never fully commissioned. A similar demonstration plant located at the Tennessee Valley Authority (TVA) facility in Columbus, Mississippi, United States, was never completed.

Chemistry Two different salt solution electrolytes are contained in two separate tanks. When energy is required, a solution of Na2S2 (sodium disulfide) is pumped to the anode, and NaBr3 (sodium tribromide) is pumped to the cathode. The anode and cathode, along with their corresponding salt solutions, are separated by an ion exchange membrane. At the negative electrode, the anodic reaction is:

2 N a 2 S 2 → N a 2 S 4 + 2 N a + + 2 e − {\displaystyle 2\ \mathrm {Na_{2}S_{2}} \rightarrow \mathrm {Na_{2}S_{4}} +2\ \mathrm {Na^{+}} +2\ \mathrm {e} ^{-}}

At the positive electrode, the cathodic reaction is:

N a B r 3 + 2 N a + + 2 e − → 3 N a B r {\displaystyle \mathrm {NaBr_{3}} +2\ \mathrm {Na^{+}} +2\ \mathrm {e} ^{-}\rightarrow 3\ \mathrm {NaBr} }

As energy is drawn from the system, the sodium disulfide becomes sodium polysulfide, and the sodium tribromide becomes sodium bromide. This reaction can be reversed when a current is supplied to the electrodes, and the system's chemical salts are recharged. The system is sometimes defined as a fuel cell because the electrodes are not consumed by the reaction; they act only as a surface for the reaction. However, the liquid is not a fuel that is consumed—it is a salt solution electrolyte that is changed by the process.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Polysulfide–bromide battery

Start with the simplest possible case. Write down what Polysulfide–bromide battery claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Polysulfide–bromide battery before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Polysulfide–bromide battery ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Polysulfide–bromide battery

In research: Polysulfide–bromide battery appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Polysulfide–bromide battery in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Polysulfide–bromide battery is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electrochemical cells, Flow batteries, Sodium, so understanding it makes those chapters shorter.
In everyday life: Look for Polysulfide–bromide battery outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Polysulfide–bromide battery in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Polysulfide–bromide battery means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Polysulfide–bromide battery out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Polysulfide–bromide battery in simple terms?

Why does Polysulfide–bromide battery matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Polysulfide–bromide battery?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Polysulfide–bromide battery.