The
country that wants to rule the world of electric bikes by using salt-powered
batteries
Dozens of
shiny electric mopeds (motorcycles) line up outside a shopping mall in the
eastern Chinese city of Hangzhou, attracting the attention of passersby who can
take a test drive of the electric bikes.
Harmony
with the ‘small electric donkey’
Motorcycles
or bikes, i.e. two-wheeled vehicles, are a very popular means of transportation
in many Asian countries. They are seen everywhere in China and are used by a
large number of people to get from one place to another. Due to their
practicality and versatile nature, the Chinese people have nicknamed them
‘small electric donkeys’.
“Two-wheeled
vehicles (bikes) are usually driven for short distances and at low speeds, so
they consume less energy and power,” says Chen Shi, a researcher at the Xi’an
Jiaotong Liverpool University in China.
He says that
sodium-ion batteries have significantly less energy than lithium-ion batteries
of the same size, meaning they have a lower energy density.
The main
competition for sodium-ion batteries for these vehicles is lead-acid batteries,
whose energy density and recharge cycle are both lower than sodium batteries.
Chen Shi says their only advantage is that they are currently cheaper than both
sodium and lithium-ion batteries.
Bikes are in
high demand in Asia, and mass production of them offers a promising path for
this type of battery-powered vehicle. According to Shanghai-based consultancy
iResearch, about 55 million electric bikes were sold in China alone in 2023,
about six times the total number of all full, hybrid and fuel-cell electric
cars sold in the country in the same period.
Yadia also
aims for mass production. Mr. Zhu said on the talk show that the company wants
to bring sodium batteries to millions of ordinary commuters. He said that the
goal is to make them accessible to the public not only by installing these
batteries in bikes, but also by developing a charging system that makes these
vehicles easy to use and the system easily accessible.
A whole
system is being developed city by city for charging vehicle batteries, image
source
To assess
the situation in 2024, Yadia launched a pilot program in Shenzhen. Shenzhen is
a large city in southern China with a population of 17.8 million. According to
Shenzhen News, 150,000 food delivery couriers were included in the pilot
program.
Yadia’s goal
was for couriers to deposit their empty sodium-ion batteries at Yadia’s partner
battery swapping stations and receive a fully charged battery within just 30
seconds.
Yadia and
other battery swapping companies such as Dodo Huandian are growing rapidly in
Shenzhen. Now the city wants to make itself a ‘battery swapping city’.
According to
the Shenzhen Electric Bicycle Industry Association, the city plans to install
20,000 charging or battery swapping pods for various types of electric scooters
by 2025, and increase the number to 50,000 by 2027.
The trade
body is working with the Shenzhen government to promote battery swapping. The
city already has a “battery-swapping park.” And according to the association, a
network will be set up in the future so that there is a battery-swapping
station every five minutes.
Rise and
fall
Sodium-ion
and lithium-ion batteries have the same structure. The main difference is that
they use different types of ions. Ions are particles that store and release
energy by moving between the positive and negative ends of the battery.
Sodium is
found in vast quantities in the ocean and underground, and is about 400 times
more abundant than lithium. Therefore, sodium-ion batteries can be made
relatively more accessible and affordable on a large scale. It could also help
relieve the battery industry of the current supply chain problems.
Currently,
lithium is mostly mined in Australia, China and Chile, but about 60% of its
processing takes place in China, which is the largest lithium refining center
worldwide.
Energy
storage stations for emerging sodium-ion technology
Sodium-ion
batteries are not a new invention. Their development journey is intertwined
with lithium-ion batteries. Research on both types began in Japan about half a
century ago. But when Japanese electronics company Sony introduced the world's
first lithium-ion battery in 1991, its commercial success stalled the
development of sodium-ion technology. The situation remained the same until the
beginning of this decade. But then China became the world's largest battery power
thanks to government industrial efforts.
2021 proved
to be a turning point for sodium-ion batteries. Demand for electric vehicles
(EVs) and the COVID-19 pandemic have sent lithium prices soaring, more than
quadrupling in a year. As a result, battery and EV companies have begun looking
for alternatives.
In July this
year, CATL launched its first sodium-ion battery, which “sparked a lot of
interest in the industry,” according to Fat Zhang, founder of Shanghai-based EV
news outlet CNEV Post. Lithium prices rose further in 2022, which has led
Chinese companies to turn to sodium.
“The
abundant availability of sodium and China’s interest in a robust battery supply
chain have been central to the research and development efforts,” says Kate
Logan, director of the Asia Society Policy Institute in Washington, D.C., who
works on China’s environmental and energy policies.
At the time,
China was importing about 80 percent of its lithium needs from Australia and
Brazil.
But lithium
prices began to fall sharply in late 2022 and are now well below their peak.
According to Zhang, one reason for this is that Chinese companies such as CATL
and Guotian have increased their lithium processing capacity. China has also
stepped up efforts to find and develop local lithium reserves.
As a result,
the “mania” around sodium-ion batteries that was seen in the past few years has
now “faded.” According to Combs, “lithium has once again firmly returned to a
leadership role in China.”
Focus on
safety
But for
many, another important reason for adopting sodium-ion batteries is their
‘safety’.
In 2024, a
series of battery fires in China shocked everyone. Most of the fires were
caused by lithium-ion batteries in bicycles spontaneously catching fire.
There has
been global concern about the risks of fires in energy storage stations. In a
recent incident, a fire broke out inside a large battery plant in California in
January 2025.
Some
industry experts believe that sodium-ion batteries are safer. According to some
research, the more stable chemical properties of sodium make these batteries
less likely to overheat or catch fire. However, other experts warn that it is
too early to say anything definitive about their safety, as more research is
needed in this regard.
Cold weather
also affects the performance of batteries. At sub-zero temperatures, the energy
storage capacity and number of charging cycles of lithium-ion batteries decrease.
Sodium-ion batteries, on the other hand, are less affected by harsh weather
conditions.
“Sodium ions
move more easily in the liquid inside the battery than lithium ions,” says Tang
Wei, a professor of chemical engineering at Xi’an Jiaotong University in China.
This improves their electrical conductivity and requires less energy to break
free from the liquid around them.
Tang Wei and
his team have developed a new battery liquid that they say enables sodium-ion
batteries to operate at more than 80 percent capacity even at minus 40 degrees
Celsius (−40F). They are working with Chinese battery companies to apply the
technology to vehicles and energy storage stations in cold regions of the
country.
Sodium-ion
batteries are also expected to reduce the environmental impact of the
production of metals used in lithium-ion batteries, especially cobalt and
nickel. These heavy metals can be harmful to both humans and the environment.
A 2024 study
concluded that sodium-ion batteries could save the world from over-mining and
potential shortages of valuable raw materials, but their production process
produces the same amount of greenhouse gas emissions as lithium-ion batteries.
Zhang Shan,
the lead author of the study and a researcher at Chalmers University of
Technology in Gothenburg, Sweden, says: “Since these batteries are still in
development, their production, duration, and energy density can be improved.
And in the future, their environmental impact may be lower than that of
lithium-ion batteries.’
Powering
four-wheeled vehicles
The first
electric cars powered by sodium batteries began rolling out of factories in
December 2023. All models available so far have been microcars, which are
classified as A00 in China.
Sing Li, an
independent analyst of the Chinese auto industry, said that their sales were
very modest compared to the millions of EVs sold in China in 2024 (only 204
vehicles were sold, according to one report).
A major
drawback of sodium-ion batteries is their low energy density. According to a
2020 study, their density is at least 30% lower than that of lithium-ion
batteries. This means that such vehicles cannot travel as far on a single charge.
“And when
people buy EVs, the range of the vehicle is a huge and decisive factor for
them,” says Zhang.
“Sodium-ion
batteries have not yet been mass-produced and currently cannot compete with
lithium-ion batteries in four-wheeled vehicles in terms of price or
performance. It is difficult to see them being used on a large scale in the
next two or three years.”
The use of
sodium-powered scooters across China is growing slowly but encouragingly. Yadia
sold more than 13 million electric bikes and mopeds worldwide in 2024.
A Yadia
spokesperson told the BBC that sales of its sodium two-wheeled vehicles reached
about 1,000 units in the first quarter of 2025. “The company plans to build
about 1,000 fast-charging pillars dedicated to sodium-ion batteries in Hangzhou
this year, so that commuters can have one charging station every 2 kilometers,”
Zhu told a talk show.
Yadia is not
the only company promoting sodium batteries. Another Chinese scooter maker,
Tailang, is selling sodium-based models from 2023. According to local media,
FinDreams, the battery wing of electric vehicle giant BYD, has started building
a plant to produce sodium batteries in the eastern Chinese city of Xuzhou with
Huaihai Group, a manufacturer of two- and three-wheeled vehicles.
Although lead-acid
batteries will continue to dominate the industry, sodium-ion batteries are
expected to gain market share rapidly over the next five years. According to an
analytical report by the Shenzhen-based Starting Point Research Institute, 15%
of China's electric scooters will be powered by sodium batteries by 2030,
compared to just 0.04% in 2023.
Greening
the grid
A big
potential market for sodium-ion batteries could actually be energy storage
stations, which store electricity generated at a given time for later use.
When these
batteries are permanently installed, all the drawbacks that come with using
them in vehicles become irrelevant.
“You can just
build a slightly larger energy storage plant,” says Combs. “It’s not going
anywhere. And the weight of the batteries doesn’t matter.”
Energy
storage is set to become a huge and fast-growing market in the future as
countries around the world strive to meet their environmental goals.
According to
the International Energy Agency (IEA), if the world wants to achieve net zero
by 2050, the energy storage capacity in the global grid will need to increase
by about 35 times between 2022 and 2030.
“This is
going to be a really important market in the future, especially as the share of
renewable energy on the grid increases,” says Ilaria Mazzocco, a senior fellow
at the Center for Strategic and International Studies in Washington, D.C.
“There will be a greater need for storage systems to balance out fluctuations
in electricity generation.”
She says
that the use of sodium-ion batteries in energy storage stations is also
beneficial because these facilities are not competing with auto companies in
making batteries for vehicles.
While China
has seen rapid growth in wind and solar power plants, it is also making the
most of energy storage to promote renewable energy worldwide.
In May 2024,
China put into operation its first sodium-ion battery-powered energy storage
facility. The plant is located in the southern Chinese province of Guangxi.
According to
Chinese state media, it can store 10 megawatt-hours of electricity at a time,
equivalent to the daily power needs of 1,500 homes. The project is actually part
of the first phase of a larger station, which will have a capacity ten times
that.
The Guangxi
project was followed by another sodium-ion energy storage project in central
China’s Hubei province. In fact, according to Beijing, a Chinese news outlet
that tracks the power industry, sodium technology will account for about a
fifth of the total capacity of all energy storage projects planned by Chinese
state-owned companies by 2023.
But the real
question for mass production of sodium-ion batteries is whether companies can
make them cheaper than lithium-ion batteries? That is the main challenge, says
Zheng Jiayu, a consultant specializing in the energy storage supply chain at
Wood Mackenzie.
Currently,
the per-unit price of sodium-ion batteries for energy storage is about 60
percent higher than lithium-ion batteries, but this gap is likely to narrow in
the future, according to an analysis by the Beijing-based non-profit
organization China Energy Storage Alliance, according to a report by China
Central Television.
China
poised to lead
Some
entrepreneurs and researchers believe that sodium is an alternative that could
help other countries reduce their reliance on China.
But if the
technology becomes widely successful, Chinese companies will lead global
production. According to Combs, China’s major battery makers have included
sodium in their long-term strategies to stay competitive globally. This means
that sodium-ion batteries can no longer escape Chinese dominance.
Zheng says
that the “biggest difference” between Chinese companies and those in other
countries is that it is much faster in China to bring a technology from the
laboratory to mass production.
According to
Logan, because the design of lithium-ion and sodium-ion batteries is very
similar, China’s existing battery manufacturing infrastructure can be used to
manufacture sodium batteries with minor modifications, reducing the time and
cost to commercialization.
However, she
adds, “this convergence is not necessarily true for other battery chemistries.”
For example,
Moke, founder of Beijing-based battery research firm Real Li Research, said
that all-solid-state batteries do not use liquid electrolytes, which are the
basis for ion transport in current-generation batteries. Moke believes that
these batteries will therefore be less dependent on the existing industrial
supply chain.
China is now
building large-scale factories to produce sodium-ion cells, some of which have
already started operating. According to Gaogong Industrial Research, by 2024,
Chinese manufacturers have announced plans to build 27 sodium-ion battery
plants with a total capacity of 180 gigawatt-hours, including BYD’s 30-gigawatt
plant in Shuozhou.
Citing Wood
Mackenzie’s analysis, Zheng says that by 2033, the world’s planned sodium-ion
battery capacity will exceed 500 GWh, with China accounting for more than 90
percent of that.
Outside
China, the U.S.’s Neutron Energy and Britain’s Frieden are the leading players
in the field. But according to Zheng, foreign companies generally take longer
to build production lines, and it is difficult to compete with China in terms
of production capacity.
According to
Alicia Garcia Herrero, an economist and senior fellow at the Brussels-based
think tank Brugel, Chinese companies spent more than 55 billion yuan (about
$7.6 billion) on sodium-ion battery research and development in 2023 alone, far
exceeding the total $4.5 billion raised by U.S. non-lithium battery startups by
2023.
According to
Combs, the Chinese companies’ strategy is simple: “not to lose market share and
to be involved in the future market.” According to Zhao, Yadia is also expanding
its activities in Southeast Asia, Latin America and Africa, where electric
scooters are very popular. According to Zhao, Yadia’s goal is clear: to mass
produce sodium-ion batteries and improve the charging infrastructure for
scooters “so that millions of people can benefit from green transport.”