What Is the Story: What Remains When You Remove the Anode Material
The real contest in anode-free batteries is not “removing the anode material” but “what takes over the job the anode material used to do — receiving lithium evenly.” Recent patents are converging on coating the current collector surface with a functional layer only a few nanometers thick to take on this role. US11848446B2, examined in this piece, likewise claims a configuration that places a transition metal dichalcogenide layer together with an intermediate layer on a copper current collector.
Starting with the industry context, there is a persistent expectation that a working anode-free battery could reshape the market. True to the name, it has no anode active material (the material that stores lithium); instead, lithium metal builds up on the current collector surface only during charging and acts as the anode. It is in theory the lightest possible anode, yet the prevailing view in the industry is still that “a battery without an anode material is effectively out of reach.”
That is where the tension arises. The ceiling on energy density is clearly high, but cycle life and safety still cannot match commercial graphite anodes. This piece answers three questions. First, why is cycle life short in an anode-free structure? Second, through what claimed configuration does US11848446B2 try to solve the problem, and how far does its scope of rights extend? Third, what should planning and IP staff be tracking in this space?
Basic Mechanism: Catching Water Without a Container
A conventional lithium-ion battery stores lithium by loading an active material such as graphite or silicon into the anode. An anode-free battery removes this active material and leaves only the copper current collector. During charging, lithium ions released from the cathode are deposited (built up as a thin layer on the surface) onto the copper current collector in metallic form; during discharge, they become ions again and return to the cathode.
Source: reconstructed by the editorial team from the claims and specification of US11848446B2
By analogy, a graphite anode is a tightly partitioned “egg carton.” Each lithium has a set place to go, so you can predict where and how many will fit. An anode-free structure is like pouring eggs onto a flat tray with no carton. The eggs pile up wherever they land first, and some stack into towers. In a battery, these “towers” are needle-shaped lithium crystals called dendrites, and if they pierce the separator they can lead to a short circuit.
With no active material, raw-material, solvent, and processing costs fall, and the weight and volume used to hold lithium inside the cell can be minimized — that is the advantage. The problem is that, without the “container,” lithium does not deposit uniformly, and the volume expands and contracts sharply on every charge and discharge. Because an anode-free cell has no excess lithium from the start, any lithium lost to side reactions shows up directly as capacity loss. That is the structural reason cycle life deteriorates so quickly.
- Key metric: Coulombic efficiency (the share of lithium plated during charging that returns during discharge). The gap between 99% and 99.9% widens into a large capacity difference after a few hundred cycles.
- Directions for solutions: they split into three paths — improving electrolyte composition, adopting solid electrolytes, and modifying the current collector surface (functional-layer coatings).
Comparison: Expectations and Reality of Anode-Free, in Numbers
Comparing the theoretical capacity of the anode materials themselves first, lithium metal can hold roughly 10 times more lithium per unit weight than graphite. An anode-free structure goes one step further and does not even pre-load lithium metal foil.
| Category | Theoretical specific capacity (mAh/g) | Anode state at cell assembly | Main challenge |
|---|---|---|---|
| Graphite anode | 372 | Graphite active material coating | Approaching its capacity limit |
| Lithium-metal anode | 3,860 | Lithium metal foil attached | Dendrites, cost of excess lithium |
| Anode-free | Lithium metal basis (supplied from the cathode) | Copper current collector only | Uneven deposition, cumulative lithium loss |
Source: compiled by the editorial team from the graphite and lithium-metal theoretical capacities in Rahman et al., Electrochemical Energy Reviews (2025, ORNL public abstract)
What this table says: The theoretical capacity of lithium metal (3,860 mAh/g) is about 10.4 times that of graphite (372 mAh/g). The anode-free structure is the lightest way to tap this potential, but because it has no excess lithium, its cycle-life challenge is exposed most sharply.
So how far has cycle life actually come in research? The table below places three representative published cases side by side. Test conditions all differ, so they cannot be ranked directly; the table is meant to show “which approach has been reported to reach what level.”
| Case | Approach | Reported figures |
|---|---|---|
| Weber et al., Nature Energy (2019), Dalhousie University | Improved liquid electrolyte (LiDFOB/LiBF₄ dual salt) | Anode-free pouch cell, 80% capacity retained after 90 cycles |
| Lee et al., Nature Energy (2020), Samsung Advanced Institute of Technology | Sulfide solid electrolyte + thin Ag–C (silver-carbon) layer | Pouch cell above 900 Wh/L, 1,000 cycles, Coulombic efficiency above 99.8% |
| US11848446B2 examples, Korea University of Technology and Education Industry-University Cooperation Foundation | PdTe₂ layer (+LiPON layer) on copper current collector | PdTe₂+LiPON: Coulombic efficiency of 95% or more over 150 cycles; bare copper about 70% after 100 cycles |
Source: compiled by the editorial team from the abstracts of the Nature Energy papers (2019, 2020), and the US11848446B2 specification (Google Patents)
What this table says: A case combining a solid electrolyte with a functional layer has been reported at around 1,000 cycles, while liquid-electrolyte-based cases are often presented at around 100 cycles. Functional-layer coatings are a “common component” that can sit on top of either approach, which makes them a point where patent competition tends to concentrate.
Patent Perspective: Scope of Rights and Design-Around Points of US11848446B2
Bibliographic data: US11848446B2 (title: “Anode-free rechargeable lithium battery including transition metal dichalcogenide layer and method of manufacturing same”) names the Industry University Cooperation Foundation of Korea University of Technology and Education as both applicant and current rights holder. Its priority application is Korean patent application 10-2021-0096212 (2021-07-22); the US filing date is 2021-11-11, it was published as US20230022140A1 (2023-01-26), and it was granted on 2023-12-19. Google Patents lists its legal status as Active, with an anticipated expiration date of 2042-04-13.
Gist of the claims (restated): Independent claim 1 covers an anode-free lithium metal battery with a cathode, a negative electrode current collector, an electrolyte, and a separator, in which the negative electrode current collector includes both (1) a transition metal dichalcogenide (TMD, a layered compound of a transition metal bonded with sulfur, selenium, or tellurium) layer satisfying the formula MX₂ and (2) a transition metal intermediate layer satisfying the formula MX. Here M is selected from Pd, Pt, Cu, Ag, and Au, and X from S, Se, and Te. The dependent claims add an artificial SEI (solid-electrolyte interphase) layer (claim 2), a TMD layer thickness of 2-20 nm (claim 3), and an artificial SEI layer containing LiPON (lithium phosphorus oxynitride) (claim 4).
Source: reconstructed by the editorial team from claim 1 of US11848446B2 (as published on Justia Patents)
The specification describes a manufacturing method that deposits the TMD on copper foil by magnetron sputtering while heat-treating at 150-250°C, and states that a CuTe intermediate layer forms through metallic bonding in the process. In other words, the “intermediate layer” in claim 1 can be read not as a separately stacked layer but as a layer that arises at the interface during processing.
Design-around points and infringement exposure: The literal scope of rights of claim 1 is limited to the simultaneous presence of “an MX₂ layer + an MX intermediate layer” and to the Markush (listed-alternatives) range of the M and X elements. The following design-around options can therefore be considered.
- Element-selection design-around: The M list in claim 1 does not include elements such as Mo or W. A design using a TMD outside the list, such as MoS₂, may lower the risk of literal infringement.
- Layer-configuration design-around: A single-TMD-layer structure without the intermediate layer (MX) lacks one element and may fall outside literal infringement.
- Switching functional-layer families: A non-chalcogenide deposition-guiding layer, such as a silver-carbon composite layer, differs from the chemical-formula requirement of claim 1.
Design-around scenario (counter-argument): That said, the argument “we did not provide an intermediate layer” may be weaker than it looks. When a Pd-Te-based layer is formed on a copper current collector by heat treatment, an MX interfacial layer such as CuTe may naturally form in the process, in which case it could be argued that the claimed configuration is met regardless of design intent. A design-around by swapping elements may also be subject to the doctrine of equivalents (the legal principle that treats a substituted element as infringing if it is substantially the same), so documenting cross-sectional analysis data and the differences in function and effect of the substituted element in advance serves as a defensive shield in an FTO (freedom-to-operate) assessment.
In terms of filing history, it is also worth noting that this patent is held by a university industry-cooperation foundation. University-held patents are often exploited through technology transfer and licensing rather than direct practice, so for companies seeking to enter this field, license negotiation alongside design-around can be a realistic option.
Limits and Outlook: Functional-Layer Patents Will Grow, but the Bottleneck Lies Elsewhere
In the industry, graphite anode technology is seen as having been optimized over a long period to a point where there is not much room left for improvement. Even so, anode-free batteries are widely assessed as still at “the stage of verifying whether it is structurally possible.” Since no technology has yet fully solved uneven lithium-metal deposition, patents in this field are likely to keep growing for the time being in the direction of diversifying “deposition-guide layer” materials such as TMD layers.
Counter-scenario: Even if functional-layer patents increase, commercialization may not come any sooner. As the comparison table shows, liquid-electrolyte-based cases are often presented in the 100-150-cycle range, and cases at the 1,000-cycle level assume a solid electrolyte and a pressurized process. If the bottleneck lies not in the current collector coating but in the electrolyte, cell pressure, and process equipment, coating-material patents alone may have limited business value.
Strategic alternative: Rather than only stacking up material-composition claims, it is effective to also secure rights to “how the coating is made and how it is verified.” As the US11848446B2 specification shows, process and verification elements such as sputtering conditions, heat-treatment temperature, and interfacial-layer formation make competitors’ design-arounds harder and create an evidentiary structure that helps prove infringement.
Practical action: List the current collector coating materials for anode-free and lithium-metal anodes used by your company or partners, and run a first-pass cross-sectional analysis to check whether each material’s metal element (M) and chalcogen element (X) fall within the alternatives of claim 1 of US11848446B2 (Pd, Pt, Cu, Ag, Au / S, Se, Te), and whether an MX intermediate layer forms at the interface after heat treatment.
Items requiring verification
- Whether Korean priority application 10-2021-0096212 has been granted, and the scope of its Korean claims
- The exact family relationship between US11848446B2 and US20220223868A1
- The basis in the specification for the earlier description that the design “reuses existing binder and conductive-additive materials as-is” (not confirmed within the scope reviewed this time)
- Corresponding patent numbers and rights holders for competing functional-layer technologies such as the Ag–C layer
Sources
- US11848446B2 bibliographic data and specification, Google Patents
- US 11,848,446 claims, Justia Patents
- Weber, R. et al., “Long cycle life and dendrite-free lithium morphology in anode-free lithium pouch cells enabled by a dual-salt liquid electrolyte”, Nature Energy (2019)
- Lee, Y.-G. et al., “High-energy long-cycling all-solid-state lithium metal batteries enabled by silver–carbon composite anodes”, Nature Energy (2020)
- Rahman, M. M. et al., “Valuation of Anode Materials for High-Performance Lithium Batteries: From Graphite to Lithium Metal and Beyond”, Electrochemical Energy Reviews (2025), ORNL public abstract