The 5C-rated Kirin battery, developed by Contemporary Amperex Technology (CATL). Header image source: CATL.
Solid-state batteries, prized for their thermally stable electrolytes, promise longer range and higher safety and are widely viewed as the ultimate form of power battery technology. Yet despite years of investment, persistent technical, manufacturing, and cost barriers have kept them confined to laboratories, far from commercial mass production.
Recently, however, several second- and third-tier battery makers, along with automakers such as Chery, have announced new R&D progress, rekindling optimism about their future viability.
On October 23, Sunwoda unveiled its solid-state battery, “Xin Bixiao,” claiming an energy density of 400 watt-hours per kilogram. For comparison, mainstream lithium iron phosphate (LFP) batteries range between 200–250 watt-hours per kilogram, while ternary lithium batteries reach around 250–300 watt-hours per kilogram.
The new battery reportedly operates across a temperature range of –30 to 60 degrees Celsius and has a cycle life of 1,200 weeks. Sunwoda also announced plans to complete a 0.2 gigawatt-hours pilot line for polymer solid-state cells by the end of this year, and said it has successfully developed and tested a 520 Wh/kg lithium metal “super battery” in the lab.
Just days earlier, on October 18, Chery unveiled Rhino S, its self-developed all-solid-state battery module, boasting an energy density of 600 Wh/kg and a projected driving range of 1,200–1,300 kilometers once installed in vehicles. Chery aims to begin mass production in 2027.
The combined publicity push from battery manufacturers and automakers, amplified by recent car fire incidents, has thrust solid-state batteries back into the public spotlight.
Yet despite the renewed attention, experts remain cautious: large-scale commercialization is still years away.
During a July earnings call, Contemporary Amperex Technology (CATL) said limited production could start in 2027, with mass production likely around 2030. CATL chairman Robin Zeng noted last year that if solid-state battery maturity were rated on a nine-point scale, the industry is currently at “four.”
Sunwoda is even more conservative. At its latest event, a company executive remarked that claims by Japanese and US firms to industrialize all-solid-state batteries by 2027 were overly optimistic. The best-case scenario, he said, would see limited production after 2030.
Even Chery, which once targeted 2027 for mass production, has since adjusted expectations, aiming instead to release its first batch of validation vehicles that year.
Why solid-state batteries remain stuck in the lab
A core technical challenge lies in the poor ionic conductivity of solid electrolytes and the high impedance at the solid-solid interface.
Liquid electrolytes fully permeate electrodes, forming continuous ion channels. By contrast, solid electrolytes make only surface contact, weakening ion transport. During charging and discharging, the anode expands and contracts as lithium ions move, creating microscopic gaps that interrupt conductivity. This is why finding materials that combine high energy density with stable interface contact remains one of the most difficult goals in battery research.
An industry insider told 36Kr that most companies currently use cathode materials comprising nickel and manganese at a ratio of nine to one, similar to high-nickel ternary lithium batteries. Because high-nickel materials are already widely used in ternary lithium batteries, companies such as CATL can leverage their existing technical expertise in that field to accelerate solid-state battery development.
The debate over electrolyte materials is even more divisive.
According to Zhu Xingbao, chief scientist at Gotion High-tech, there are six main technical routes. The earliest, polymer-based electrolytes, are easy to process and self-healing but conduct poorly unless heated to 60–80 degrees Celsius.
Then came oxide-based electrolytes, which offer stability and conductivity but are brittle and prone to cracking.
Today, the mainstream focus has shifted to sulfide-based electrolytes, which rival liquid electrolytes in ionic conductivity but are highly sensitive to moisture. When exposed to air, they degrade rapidly and emit hydrogen sulfide gas. Other experimental routes—halide, borohydride, and thin-film electrolytes—are also under exploration.
Several insiders told 36Kr that despite their superior conductivity, sulfides are difficult to scale. Their toxicity and air sensitivity demand sealed, corrosion-resistant, fully automated production environments. These conditions make yield control and consistency particularly challenging.
Researchers are also experimenting with interface modification techniques. According to Xinhua, scientists have tested adding iodine ions to the electrolyte to form an iodine-rich interfacial layer that fills microscopic gaps and improves lithium-ion transport. However, one analyst noted that iodine tends to reduce to elemental iodine, which then accumulates at the interface, limiting long-term effectiveness.
Beyond electrolytes, anode materials pose another major challenge.
An engineer at a leading battery manufacturer explained that while graphite can serve as a solid-state anode, it offers relatively low energy density. Most developers therefore favor silicon-carbon anodes, which combine silicon’s high capacity with graphite’s stability. However, silicon expands significantly during lithium-ion insertion, causing the anode to swell and contract with each cycle—a process that sharply shortens battery lifespan.
Manufacturing and cost hurdles
Manufacturing remains another bottleneck.
According to Gotion’s Zhu, transitioning from liquid to semi-solid batteries alters only about 3–5% of existing production lines, but fully solid-state batteries require far more extensive changes. Pan Ruijun, chief engineer of Gotion’s solid-state battery project, said at least 60% of equipment for the firm’s experimental line had to be rebuilt.
The most difficult step is electrolyte coating. Solid-state batteries require ultra thin coatings, precise film formation, and high-temperature processing without separators. This means separators must effectively be created through coating and embedded between electrodes, and this process alone can take years to perfect, according to Pan .
Because solid-state production diverges so much from conventional lithium battery manufacturing, many companies view semi-solid batteries as a transitional step, leveraging existing equipment while gradually upgrading processes toward full solid-state capability.
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Yet technical complexity is only part of the problem.
Yang Hongxin, chairman of Svolt Energy Technology, said publicly that all-solid-state batteries currently cost five to ten times more than liquid lithium batteries. Given that batteries already account for more than 30% of an electric vehicle’s total cost, such premiums would be prohibitive for both automakers and consumers.
In short, the business model for solid-state batteries still doesn’t add up.
So why does the technology continue to attract so much attention despite its distant timeline?
For smaller battery makers, it represents a rare opportunity to leapfrog incumbents like CATL through a paradigm shift in technology. For automakers, it offers the possibility of greater bargaining power with dominant suppliers. And for consumers, a recent wave of EV fire incidents has revived concerns over liquid battery safety, fueling hopes for a safer, higher-density alternative.
But amid the renewed enthusiasm, one fact remains: solid-state batteries are still a technology of the future, one that may not reach mass production even by 2027.
KrASIA Connection features translated and adapted content that was originally published by 36Kr. This article was written by Fan Shuqi for 36Kr.