Electrochemistry, rechargeable batteries and fuel cells

Electrochemistry Fundamentals

Electrochemical cells convert chemical energy into electrical energy by a spontaneous redox reaction.
Comprises of two half-cells, each containing an electrode (conductor) and an electrolyte (ionic conductor), connected via with a salt bridge.

Galvanic Cells

In galvanic cells, also known as voltaic cells, the electrochemical process is spontaneous and produces electrical energy.
Zinc-copper battery is a common example. Zinc undergoes oxidation (loses electrons) while copper undergoes reduction (gains electrons).
The energy produced is used to operate devices.

Electrolytic Cells

Electrolytic cells use electrical energy to drive a non-spontaneous reaction.
Often used to decompose compounds, such as splitting water into hydrogen and oxygen using electricity.

Rechargeable Batteries

Rechargeable batteries, like lithium-ion batteries, are a common application of electrochemistry.
During use (discharging), they act as a galvanic cell, converting stored chemical energy into electrical energy.
They can be recharged (with electrical energy), acting as an electrolytic cell, and stores it as chemical energy for future use.

Fuel Cells

A fuel cell is a special type of galvanic cell that converts the chemical energy from a fuel into electricity through an electrochemical reaction with an oxidising agent.
In hydrogen-oxygen fuel cells, hydrogen and oxygen are continuously supplied, reacting to produce water while also generating an electric current.
Fuel cells have high energy efficiency, and their only by-product, water, is environmentally friendly. They’re often used in space crafts and electric vehicles.

Environmental Impact and Sustainability

Despite lithium-ion batteries’ efficiency and high energy density, mining of lithium and cobalt (used in the batteries) has environmental and human rights concerns.
Fuel cells, while having a clean by-product, struggle with the issue of sourcing and storing hydrogen, which can also have an environmental impact.
Development of new materials and technologies can potentially overcome these challenges to provide greener, more sustainable energy storage.