From Dead Frogs to Dream Batteries: The Great Journey That Changed the World

Delving into the tiny energy storage device in our pockets: everything about batteries.

• Discover the strange scientific experiment that marked the beginning of batteries.
• Understand the operating principles of lithium-ion batteries, the core of modern society.
• Examine the possibilities and challenges of future battery technologies like solid-state and sodium-ion.

Prologue: Can you imagine a world without wires?

Waking up to a smartphone alarm, brushing your teeth with an electric toothbrush, and listening to music on wireless earbuds—our daily life begins with countless wireless devices. At the center of all this convenience is a small energy storage device quietly powering the world from our pockets and bags: the battery.

We take batteries for granted, but inside this small box lies over 200 years of scientists’ dedication, fierce competition, and world-changing innovation. From the hind legs of dead frogs to the ‘dream batteries’ that will power humanity’s future, let’s follow the great chronicle of batteries through the ages.

Chapter 1: The Dawn of Batteries – Dead Frogs and the Debate of Two Scientists

1.1 Luigi Galvani’s Accidental Discovery and ‘Animal Electricity’

The history of batteries begins in 18th-century Italy, in the laboratory of anatomist Luigi Galvani. One day in 1786, his wife noticed that a frog’s leg placed on a metal plate for cooking twitched when sparks from a nearby static electricity device occurred.

Fascinated by this strange phenomenon, Galvani conducted further experiments and concluded that a special electricity inside living beings, called ‘animal electricity’, caused muscle movement. This theory of ‘Galvanism’ caused a sensation in European society and even inspired Mary Shelley’s novel Frankenstein.

1.2 Alessandro Volta’s Rebuttal and the First Battery, the ‘Voltaic Pile’

Galvani’s friend and fellow scientist, Alessandro Volta, questioned his theory. Through experiments, he revealed that the frog’s leg twitching was not due to life but because two different metals in contact through the moist frog leg (acting as an electrolyte) generated electricity. This was a Copernican shift: electricity came from metals, not living beings.

To prove this, in 1799 Volta stacked copper and zinc plates separated by saltwater-soaked cloth, creating the first device to produce a continuous electric current: the ‘Voltaic Pile’. This invention earned Volta high praise from Napoleon, and today the unit of electric potential, the ‘volt’, is named in his honor.

The Voltaic Pile was the key to a new scientific era, sparking explosive growth in 19th-century electrochemistry, including the discovery of new elements through electrolysis. Interestingly, Galvani’s ‘animal electricity’ theory was later re-evaluated as pioneering bioelectricity, recognizing that nerves and muscles operate via tiny electrical signals. The debate between these two giants opened two great paths in science history.

Chapter 2: The Dawn of Rechargeables – Taming Electricity with Secondary Batteries

2.1 Fundamental Difference Between Primary and Secondary Batteries

The Voltaic Pile was a ‘primary battery’, usable only once. Once the internal chemical reaction ended, it could not be reversed. But humanity dreamed of ‘secondary batteries’, or rechargeables, which store electricity and can be reused by reversing the chemical reaction with external electricity.

2.2 The Unsung Hero of the Automotive Era, the Lead-Acid Battery

The first practical secondary battery was the ‘lead-acid battery’ invented in 1860 by Frenchman Gaston Planté. This battery played a crucial role in the invention of the electric starter ‘self-starter’ by inventor Charles Kettering, replacing the dangerous manual crank start.

Thanks to the lead-acid battery’s ability to supply strong initial current, anyone could safely start a car, sparking the popularization of automobiles. Remarkably, even after 160 years, most internal combustion engine cars still use lead-acid batteries for starting. Despite being heavy and having low energy density, its instant high power, high reliability, and extremely low cost make it a perfect example of a ‘good enough’ technology that has endured.

2.3 The Beginning of Portable Devices and the ‘Memory Effect’ of Nickel-Cadmium Batteries

The era of carrying electricity in your pocket began with the ‘nickel-cadmium (Ni-Cd) battery’ invented in 1899 by Swedish inventor Waldemar Jungner. Much smaller and lighter than lead-acid batteries, it enabled countless portable devices like electric shavers and radios.

However, Ni-Cd batteries suffered from a fatal ‘memory effect’: if recharged before full discharge, the battery ‘remembers’ that point as the new zero, reducing actual usage time. I vividly recall fully discharging cordless phones or drills before recharging to avoid this. Along with this inconvenience and the toxic heavy metal cadmium, Ni-Cd batteries gradually disappeared.

Chapter 3: The Heart of Modernity, the Lithium-Ion Battery Revolution

3.1 A 20-Year Relay Race Toward the Nobel Prize

The 2019 Nobel Prize in Chemistry was awarded to three scientists who opened the ‘rechargeable world.’ Their research was like a great relay race.

1. First Runner: Stanley Whittingham – In the 1970s, he established the concept of the first rechargeable battery using lithium but faced safety issues due to the explosive nature of metallic lithium.
2. Second Runner: John Goodenough – In the 1980s, he developed the innovative cathode material ‘lithium cobalt oxide (LiCoO₂)’, doubling the voltage and paving the way for smaller, more powerful batteries.
3. Third Runner: Akira Yoshino – In 1985, he replaced the explosive metallic lithium anode with a carbon material (petroleum coke) that safely stores lithium ions, finally creating a lightweight, powerful, and safe lithium-ion battery.

3.2 The ‘Rocking-Chair’ Principle: How Does a Lithium-Ion Battery Work?

The operating principle of lithium-ion batteries is likened to a ‘rocking chair’.

• Charging: Lithium ions (Li⁺) leave the cathode (+) and move to the anode (–) where they are stored. It’s like pushing a rocking chair to one side to store energy.
• Discharging: Lithium ions return from the anode to the cathode, and the electrons (e⁻) separated from the ions flow through the external circuit (smartphone, etc.), generating current. The rocking chair swings back, releasing energy.

Since lithium ions only physically shuttle back and forth without destroying the electrodes, the battery can be recharged hundreds of times.

3.3 Energy Density Driving the Mobile and Electric Vehicle Revolution

The key to lithium-ion batteries is their high ‘energy density’. They can store much more energy per weight, enabling thin, lightweight smartphones, laptops, and the ‘mobile revolution.’ Today, this technology is making electric vehicles with performance comparable to internal combustion engines a reality, leading the ‘electric revolution.’

3.4 Shadows Behind the Shining Success: Resource Dilemmas and Recycling Challenges

However, the explosive demand for lithium-ion batteries has created new problems. Key minerals like cobalt and lithium are concentrated in certain countries, causing resource weaponization and geopolitical risks, as well as human rights issues such as child labor exploitation.

Global Supply Chain of Key Lithium-Ion Battery Raw Materials

Additionally, handling spent batteries is a huge challenge. Recycling technologies (dry/wet refining) to extract key minerals from used batteries are emerging as a core future industry.

Chapter 4: The Race Toward the Future – In Search of the ‘Dream Battery’

Lithium-ion batteries are approaching their theoretical performance limits and face fire risks from liquid electrolytes and resource issues. The world is now betting everything on developing the ‘dream battery’ that surpasses lithium-ion. Which future battery technology do you have the highest hopes for?

4.1 The Ultimate Candidate: Solid-State Batteries

Among next-generation batteries, the most promising technology is the ‘All-Solid-State Battery’. By replacing flammable liquid electrolytes with nonflammable solid electrolytes, it maximizes safety and allows the use of lithium metal anodes with large energy storage capacity, dramatically increasing energy density. It’s considered a ‘game changer’ that could enable electric cars to run 800 km on a single charge.

However, challenges remain, including slow ion movement (low ionic conductivity), contact resistance between solids, and high manufacturing costs.

4.2 Practical Alternatives: The Comeback of Sodium and Sulfur

While solid-state batteries are the ultimate goal, more practical alternatives are rapidly advancing.

• Sodium-ion (Na-ion) Batteries: Using sodium, which is over 1,000 times more abundant and cheaper than lithium, these batteries offer overwhelming cost competitiveness. Though energy density is lower, they are optimized for large-scale energy storage systems (ESS) and low-cost electric vehicles.
• Lithium-Sulfur (Li-S) Batteries: With theoretical energy density 3 to 5 times that of lithium-ion, they are promising for ultra-light, high-energy applications like urban air mobility (UAM) and drones. However, they suffer from short lifespan due to byproducts formed during charge-discharge cycles.

At a Glance: Comparison of Next-Generation Battery Technologies

The future battery market will not be dominated by a single universal technology but by a coexistence of technologies leveraging their unique strengths. This is similar to choosing a car based on fuel efficiency, performance, price, and purpose. Each technology offers solutions optimized for specific purposes and will target different markets.

Conclusion: The Great Journey Continues

The faint twitch of a dead frog’s leg has become a mighty force moving the world over 200 years. Through the history of batteries, we can reaffirm three key points:

• Summary 1: Battery history advanced through accidental discoveries and intense scientific debates, as seen in Galvani and Volta’s cases.
• Summary 2: The lithium-ion battery, born from the relay research of three scientists, is the core technology that opened the modern mobile and electric vehicle era.
• Summary 3: The future will see a coexistence of various batteries optimized for specific purposes, such as solid-state and sodium-ion, ushering in a sustainable energy era.

Humanity’s journey toward batteries is more than just technological development; it is our shared story to combat climate change and build a better future. Next time you charge your smartphone, why not reflect on the 200 years of science contained within?