STEADYING ROLE. Battery energy storage systems are vital to power supply infrastructure today
Recently, Offgrid Energy Labs, a start-up incubated at IIT-Kanpur, announced it was setting up a 10 MWh pilot manufacturing facility in the UK to produce battery cells based on its proprietary ZincGel technology.
The company intends the UK plant to be a proving ground; the experience gained there, it says, will be used to establish large-scale manufacturing in India, where battery demand is expected to rise sharply as renewable energy capacity expands.
Unlike lithium-ion batteries, which rely on imported lithium, ZincGel uses zinc and bromine, both of which are abundantly available in India.
The ZincGel cell is unique in many other ways too. The basic zinc-bromine chemistry is nothing new, but it has not come into common use because of some key problems, mainly dendrite formation and hydrogen evolution reaction (HER).
Dendrites are the tiny metallic needles that emerge during repeated charging and they can pierce the separator and short-circuit the cell; hydrogen affects the cell’s efficiency by wasting a part of the charging energy and increasing internal pressure.
Offgrid Energy Labs says the key lies in its proprietary electrolyte, which makes its anode-less architecture possible. The anode-less architecture, where the anode is formed inside the cell during charging and disappears during discharging, is something that researchers have been toying with for a while. It is a mouthwatering idea because it saves the anode material completely.
Proprietary tech
Offgrid Energy Labs says it has cracked the technology. Instead of using a zinc metal anode from the outset, the battery starts with a bare current collector. During charging, zinc from the electrolyte is deposited onto this collector and dissolves back into the electrolyte during discharge. This reduces material use and simplifies cell construction.
The startup’s proprietary gel-based aqueous electrolyte, containing zinc bromide, additional zinc salts and specialised additives, prevents dendrite formation. The additives act as levelling agents and grain refiners, ensuring that zinc deposits as a dense, uniform layer instead of growing into needle-like dendrites.
The electrolyte is also designed to suppress hydrogen evolution. According to the company, proprietary additives bind free water molecules and reduce the unwanted side reactions that produce hydrogen gas.
At the positive electrode, activated carbon derived from coconut shells is used to trap bromine within its microscopic pores, thereby reducing bromine migration and improving both safety and cycle life.
Electrolyte’s role
Offgrid Energy Lab’s technology flags a significant trend in the evolution of electrochemical cell design. The electrolyte has typically been a passive medium through which ions pass from one electrode to the other. But the emerging approach — as evident in Offgrid Energy’s cell — is to expand the role of the electrolyte.
In ZincGel, the proprietary electrolyte is an active participant that performs many functions, such as suppressing dendrites and hydrogen evolution, and stabilising bromine.
The start-up, which raised $15 million from Archean Chemical Industries last year, has combined known techniques (gel electrolytes, additives, bromine-trapping carbon materials and anode-free architecture) to make a unique battery.
It says its system can deliver more than 5,000 charge-discharge cycles with round-trip efficiencies of 80-90 per cent.
Offgrid Energy is careful not to position ZincGel as a replacement for lithium-ion batteries, but as complementary in applications that require long-duration energy storage rather than high energy density.
While lithium-ion remains the preferred choice for electric vehicles and portable electronics, Offgrid Energy says zinc-bromine batteries offer advantages for grid balancing, renewable energy integration and industrial backup, where batteries are expected to discharge over 6-12 hours, operate safely over long periods and deliver thousands of charge-discharge cycles.
Published on July 13, 2026
