•

Updated Mar 21, 2026

•

3 pages

Chemical and Fuel Cells: Notes on Hydrogen-Oxygen Cells

Reuben Cowell

@reubencowell

Ever wondered how your phone battery actually works, or why... Show more

1 / 3

# 1.5.2 Chemical Cells and Fuel Cells
| Chemistry Mос

Cells and Batteries

Cells

Cells are used all the time for producing energy. The sim

Chemical Cells and Batteries

Your phone, laptop, and even that old TV remote all rely on chemical cells to work. These brilliant devices are surprisingly simple - just two different metals (called electrodes) sitting in a chemical solution (the electrolyte), connected by a wire.

Here's the clever bit: the metals react differently with the electrolyte, creating a charge difference between them. When you connect them with a wire, electrons flow from one electrode to the other, and boom - you've got electricity!

The voltage you get depends on how different your two metals are. Pick metals that are really different in reactivity (like zinc and copper), and you'll get more voltage than if you choose similar ones.

Quick Tip: Think of it like a chemical see-saw - the bigger the difference between your metals, the more "unbalanced" it gets, creating more electrical energy!

How Batteries Actually Work

A single cell doesn't give you much power, so batteries are just several cells connected together in a chain (called series). It's like adding up voltages - a 2V cell plus a 2.5V cell plus a 1.5V cell gives you 6V total.

Non-rechargeable batteries (like the ones in your TV remote) die when the chemical reactants get used up. There's no way to reverse what's happened - once they're flat, they're done.

Rechargeable batteries are much smarter. Lithium-ion batteries in your phone can reverse their chemical reactions when you plug them into the wall. The external power source forces the electrons to flow backwards, essentially "undoing" the reaction that created electricity in the first place.

Real Talk: This is why your phone battery eventually stops holding charge well - after hundreds of charge cycles, the chemical reactions become less efficient at reversing themselves.

Fuel Cells: The Future of Clean Energy

Fuel cells are like the cool, environmentally-friendly cousins of regular batteries. Instead of storing chemicals inside, they continuously take in fuel (usually hydrogen) and oxygen from the air to create electricity and water.

Hydrogen-oxygen fuel cells are becoming massive in the car industry. They're cleaner than petrol cars because they only produce water as waste, and they might even beat electric cars for being green since you don't need to mine rare metals or dispose of toxic batteries.

Here's how they work: hydrogen enters at the anode and loses electrons, creating H+ ions. Meanwhile, oxygen enters at the cathode and gains those electrons. The H+ ions travel through the electrolyte to meet the oxygen, forming water. The flowing electrons create your electricity - it's a redox reaction in action.

Future Focus: Many car manufacturers are betting big on hydrogen fuel cells as the next step beyond electric vehicles, especially for lorries and buses that need to travel long distances.

We thought you’d never ask...

What is the Knowunity AI companion?

Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.

Where can I download the Knowunity app?

You can download the app from Google Play Store and Apple App Store.

Is Knowunity really free of charge?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content in Chemistry

GCSE AQA Chemistry Topic 1

Quiz covering all of topic 1

Chemistry

Quick Runthrough of Chemistry Paper 1

FOR FT HT COMBINED & HIGHER

Chemistry

A-level OCR A Chemistry summary sheets

Everything from snaprevise for OCR chemistry a-level

Chemistry

GCSE Chemistry Revision Notes

AQA GCSE Combined Chemistry * detailed summary

Chemistry

BTEC Applied Science Unit 1 Overview

Comprehensive resource for Year 12 students pursuing a Level 3 Diploma in Applied Science. This booklet covers essential topics including cell structure, chemical properties, and wave theory, providing clear explanations and key concepts to aid in your studies and exam preparation.

Chemistry

Essential Chemistry Practicals

Explore key AQA GCSE Chemistry practicals, including flame tests, titration, and gas identification. This resource covers essential techniques for analyzing ions, making salts, and understanding reaction kinetics. Perfect for students preparing for exams and practical assessments.

Chemistry

AQA GCSE Chemistry 4.2 Bonding, structure and the Properties of Matter

4.2 Metals and Alloys

Chemistry

Redox Reactions Overview

Explore the fundamentals of redox reactions, including oxidation states, definitions of oxidation and reduction, and the roles of oxidizing and reducing agents. This summary covers key rules for determining oxidation states, the concept of disproportionation, and practical applications in chemical equations. Ideal for A-Level Chemistry students preparing for exams.

Chemistry

chem paper 1

higher

Chemistry

Most popular content

An Inspector Calls: Character Insights

Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.

English Literature

Sociology of Education Overview

Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.

Sociology

Comprehensive Crime & Deviance Overview

Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.

Sociology

Sociology of Families: Comprehensive Revision

Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.

Sociology

WJEC Unit 4 Criminology

Criminology unit 4 detailed revision note

Criminology

aqa higher tier combined science - biology b1 : cell biology, paper 1

b1: cell biology - paper 1

Biology

Criminology: Crime & Punishment Overview

Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.

Criminology

Macbeth: Guilt and Ambition

Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.

English Literature

AQA Biology: Key Concepts

Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.

Biology

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.6/5

App Store

4.7/5

Google Play

The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.

Stefan S

iOS user

This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.

Samantha Klich

Android user

Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.

Basil

Android user

This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.

David K

iOS user

The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.

Rohan U

Android user

I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.

Xander S

iOS user

THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮

Elisha

iOS user

This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now

Paul T

iOS user

Stefan S

iOS user

Samantha Klich

Android user

Anna

iOS user

Best app on earth! no words because it’s too good

Thomas R

iOS user

Basil

Android user

David K

iOS user

Sudenaz Ocak

Android user

In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.

Greenlight Bonnie

Android user

Rohan U

Android user

Xander S

iOS user

Elisha

iOS user

Paul T

iOS user

Chemistry

•

201

•

Updated Mar 21, 2026

•

3 pages

Chemical and Fuel Cells: Notes on Hydrogen-Oxygen Cells

Reuben Cowell

@reubencowell

Ever wondered how your phone battery actually works, or why electric cars are becoming so popular? Chemical cells and fuel cells are the clever bits of chemistry that power loads of the gadgets and vehicles we use every day, turning... Show more

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

Chemical Cells and Batteries

Quick Tip: Think of it like a chemical see-saw - the bigger the difference between your metals, the more "unbalanced" it gets, creating more electrical energy!

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

How Batteries Actually Work

Non-rechargeable batteries (like the ones in your TV remote) die when the chemical reactants get used up. There's no way to reverse what's happened - once they're flat, they're done.

Real Talk: This is why your phone battery eventually stops holding charge well - after hundreds of charge cycles, the chemical reactions become less efficient at reversing themselves.

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

Fuel Cells: The Future of Clean Energy

Future Focus: Many car manufacturers are betting big on hydrogen fuel cells as the next step beyond electric vehicles, especially for lorries and buses that need to travel long distances.