① What’s the Story
The turning point at which all-solid-state batteries move from being a “laboratory dream” to an “industry contesting standards” was clearly marked in August 2026, of all years. On August 21, China led the initiation of the world’s first all-solid-state battery international standard as an agenda item at the International Electrotechnical Commission (IEC), with experts from France, Japan, and Korea joining the standard-setting discussion. Around the same time, CATL disclosed an international cathode coating patent that improves the high-temperature stability of sulfide-based solid electrolytes, and Toyota and Idemitsu Kosan announced the start of construction of a pilot plant for mass-producing solid electrolyte.
To summarize the industry situation: all-solid-state batteries have long been discussed as a next-generation battery that uses a solid electrolyte instead of a liquid one to lower fire and explosion risk and, theoretically, to raise energy density as well. However, the skeptical question of “when will it be commercialized” has always followed. This is where the tension arises — as the roadmap gap among cell makers over commercialization timing widens, a competition over who first grasps the “rule-setting power” of an international standard has begun to overlap with it. Whoever secures the standard first forces later entrants to adjust their designs to match it, which is directly tied to the difficulty of patent design-arounds.
This article sets out to answer one question: how are these developments in August 2026 actually changing the cell-chemistry and patent landscape, and what should planning and IP staff check right now?
② Basic Principle — Why the “High-Temperature Stability” of Sulfide Solid Electrolytes Is the Key Issue
To picture an all-solid-state battery simply: if a conventional lithium-ion battery is a swimming pool with liquid (electrolyte solution) filling the space between the cathode and anode, an all-solid-state battery is closer to a structure that fills that same space with a rigid solid plate instead. This reduces the risk of the liquid leaking or boiling over, but it introduces a new problem: if the solid plate does not bond perfectly with the cathode and anode, the pathway for ions to travel gets cut off.
Source: reconstructed by the editorial team from the claims of US10333170B2 and WO2026045270A1
Among the various solid electrolyte materials, sulfide-based types are considered a strong candidate because of their high ionic conductivity (a measure of how well ions move). However, sulfides have a weakness: when they contact the cathode active material, they tend to react with it and decompose at high temperature. As an analogy, it is similar to tape that has good adhesion but sticks and degrades in a hot place. Because of this, recent patent filings show a split between an approach that changes the electrolyte material itself and an approach that coats a “buffer layer” on the cathode surface to block direct reaction with the electrolyte.
③ Comparison — All-Solid-State Roadmaps of Major Cell Makers
| Company | Electrolyte Family | Disclosed Target Energy Density | Mass Production/Pilot Target Timing | Notes |
|---|---|---|---|---|
| CATL | Sulfide-based | Approx. 500 Wh/kg (per company announcement) | Small-scale pilot in 2027, targeting full-scale mass production by 2030 | Scaling up to 60 Ah-class automotive cells (from 20 Ah to 60 Ah) presented as the key challenge |
| Toyota / Idemitsu | Sulfide-based | No separately disclosed figure | Targeting installation in mass-production BEVs in 2027-2028; electrolyte pilot plant completion planned for late 2027 | Pursuing production of lithium sulfide (an intermediate material) at a scale of 1,000 tons/year |
| Samsung SDI | Sulfide-based | No separately disclosed figure | Targeting 2027 mass production (pilot line operation stage) | Its 46-series cylindrical battery is already in mass production based on a conventional liquid electrolyte |
| Geely | Undisclosed | No separately disclosed figure | Battery pack completion in 2026, beginning in-vehicle verification | Plans to apply it to Volvo and Polestar |
Source: compiled by the editorial team from company announcements and press reports; energy density is the company’s stated target
What This Table Tells Us: Going by disclosed figures alone, CATL is the only company to put forward a concrete energy-density target of 500 Wh/kg, but even CATL has pinned full-scale mass production, after the small-scale pilot (2027), at 2030 — meaning no company has yet declared “finished-form mass production.” Target timing is largely clustered around 2027-2028, and the speed of actual scale-up afterward is likely to be where the real contest is decided.
④ Patent Perspective — Where Do the Scopes of Claims Diverge
The CATL international patent confirmed this time (publication number WO2026045270A1; applicant Contemporary Amperex Technology Co., Limited; inventors Wu Kai (吴凯) and five others; PCT application number PCT/CN2025/086345; priority date 2024-08-30; publication date 2026-03-05) claims the surface structure of the cathode active material. Its core claim configuration is (i) a transition-metal-oxide substrate, (ii) a Co-rich interlayer on the substrate surface, and (iii) a fluorine-based electrolyte-salt coating layer covering part of it. The core effect of this patent is that the coating layer decomposes before the sulfide electrolyte during charging, forming lithium fluoride (LiF) and thereby suppressing side reactions between the cathode and the sulfide electrolyte.
It is important that this patent’s scope of claims is limited, in every respect, to the “surface treatment structure of the cathode active material.” This places it at a different claim layer from patents dealing with the composition or crystal structure of the sulfide solid electrolyte material itself. Indeed, a cross-check shows that Toyota’s granted patent (publication number US10333170B2; applicant Toyota Motor Corp; inventor Yuki Kato; priority date 2015-02-25; grant date 2019-06-25) claims the sulfide solid electrolyte material itself — a Li-Si-P-S composition given a specific XRD crystalline phase — and does not appear to overlap in layer with the CATL patent. However, if a product emerges that implements both technologies at once (a combination of an electrolyte with a specific crystalline phase and a cobalt-coated cathode), a separate FTO (Freedom to Operate) review may be needed for that combination.
Design-Around Scenario (Counterargument): If CATL’s claims are structured to simultaneously require the functional condition that “the coating layer decomposes before the electrolyte, forming LiF” and the material condition of a “fluorine-based electrolyte salt (such as Li2PO2F2),” a later entrant has room to consider (a) adopting a buffer coating material from a family other than fluorine-based, or (b) omitting the coating layer and instead designing the composition gradient between the substrate and the Co-rich layer differently, to avoid part of the claim elements. That said, this is an area that can only be confirmed by directly comparing the full text of the claims with the prosecution history, and it should also be kept in mind that this patent is currently still under examination (Pending) in each country.
⑤ Limitations and Outlook
Viewed optimistically, with the launch of the international standard and the start of pilot-plant construction by multiple companies overlapping, all-solid-state batteries appear to have entered the actual industrial timetable starting from 2027. However, the opposing scenario must also be noted. CATL itself has stated that “the scientific challenges have largely been solved, but engineering challenges remain,” and sulfide solid-electrolyte cells are still reportedly 3-5 times more expensive than conventional lithium-ion cells. It also cannot be ruled out that, in scaling up from 20 Ah-class samples to 60 Ah-class automotive cells, the high-pressure compaction design needed to maintain interface contact could offset the weight advantage. In short, the launch of standardization does not by itself mean mass production is confirmed.
As a strategic alternative, it is worth noting that a parallel path is being pursued — entering the market first with a semi-solid approach that can use existing lithium-ion production equipment as-is, rather than going straight to full all-solid-state. U.S.-based Factorial Energy, among others, is reportedly taking this route, which can be viewed as a compromise aimed at lowering the burden of equipment investment while capturing some of the energy-density improvement early.
Action Item: Planning and IP staff are advised to check, quarterly via KIPRIS and Espacenet, whether their own (or a company of interest’s) cathode-coating and electrolyte-composition patents overlap with WO2026045270A1’s claim elements (Co-rich interlayer + fluorine-based coating), and whether this PCT application enters the national phase in the markets their own pipeline is planning to enter. Since this patent is still under examination, the possibility remains open that its claims could be narrowed or broadened during prosecution.
This article was written based on publicly available patent documents and press reports, and does not definitively guarantee any specific company’s patent grant prospects or business outcomes. Legal judgment on individual matters should always go through review by a patent attorney or other qualified professional.