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Anode-free (anodeless) batteries contain no anode active material, such as graphite, Si, or Li metal foil, at cell manufacture. During the initial charge, Li⁺ from the cathode deposits on a current collector, such as Cu, to form a metallic Li anode. Eliminating the mass and volume occupied by a conventional anode enables higher Wh/kg and Wh/L than conventional lithium-ion batteries. Anode-free batteries are therefore attracting attention as next-generation batteries for EVs, eVTOL/UAM aircraft, drones, and humanoid robots, where high energy density is essential. Recent analyses suggest that anode-free Li-metal batteries could potentially reach approximately 500 Wh/kg.

The greatest challenge in anode-free technology is its limited Li inventory. In conventional Li-metal batteries, excess Li can compensate for losses. In anode-free cells, however, the Li contained in the cathode is effectively the entire Li supply, so Li losses from SEI formation, electrolyte decomposition, and dead Li formation directly reduce capacity. Nonuniform Li nucleation on Cu also increases local current density, promoting mossy or dendritic Li growth. During stripping, some Li becomes electrically isolated, forming dead Li. The key to commercialization is therefore to maintain Li plating/stripping Coulombic efficiency as close to 100% as possible in every cycle.

Current strategies follow four main directions. First, electrolyte design uses highly concentrated electrolytes (HCEs), localized high-concentration electrolytes (LHCEs), ether-based electrolytes, and additives to reduce free solvent and side reactions while forming a LiF-rich SEI. Second, current collector functionalization promotes uniform Li nucleation using lithiophilic metals such as Ag, Zn, Mg, and Sn, as well as carbon, Cu oxides, and 3D porous Cu. Third, inorganic or polymer-based artificial SEIs and protective layers reduce direct contact between fresh Li and the electrolyte while accommodating volume changes. Fourth, Li inventory management compensates for initial Li loss through cathode prelithiation and sacrificial Li sources.

Combining anode-free architectures with all-solid-state batteries (ASSBs) has recently emerged as a major development direction beyond liquid-electrolyte systems. Solid electrolytes can reduce side reactions between Li and liquid electrolytes, but interfacial voids and contact loss after Li stripping create new challenges. In anode-free ASSBs, stack pressure, interfacial adhesion, void suppression, and mechanical compliance are therefore critical design variables alongside high ionic conductivity.

Samsung SDI, LG Energy Solution, SK On, and Hyundai/Kia are developing sulfide all-solid-state batteries and anode-free technologies in parallel. Samsung SDI is advancing anode-free ASSBs with Ag–C functional layers. LG Energy Solution improves Li nucleation and interfacial stability through LPM coatings, Cu oxidation, and 3D current collectors. SK On is studying ultrathin Ag/polymer interfaces, while Hyundai/Kia is researching low-pressure, high-loading architectures based on lithiophilic metals such as AgF and Ag/Zn. In China, CATL is developing self-forming anodes, BYD is developing 3D porous gradient collectors, and SVOLT is developing PPy/PANI–Cu and Cu₂O nanowire technologies. Ganfeng Lithium is moving from near-anode-free toward true anode-free designs through ultrathin Li and Cu–Li composites.

Commercialization of anode-free batteries is expected to bring major changes to manufacturing. Conventional anode mixing, coating, drying, and calendering steps could be substantially reduced or eliminated, while Cu foil surface modification, functional layer coating, and interface formation become more important. In conventional batteries, formation primarily stabilizes the SEI. In anode-free cells, the initial charge itself becomes an electrochemical manufacturing step that creates the Li-metal anode. Initial charging current, temperature, state of charge (SOC), rest time, and stack pressure therefore directly affect the final Li morphology and cycle life.

Near-anode-free designs using ultrathin Li or a small amount of excess Li are likely to commercialize before true anode-free designs. They retain most of the energy density advantages while preserving a small Li reservoir to compensate for initial SEI and dead Li losses. As electrolyte, current collector, interface, and Li inventory management technologies advance, Li thickness is expected to decrease from tens of micrometers to a few micrometers, ultimately reaching zero-excess architectures.

Likely early applications include drones, eVTOL/UAM aircraft, aerospace, and humanoid robots, where high energy density matters more than long cycle life. Adoption could later expand into premium EVs as large-area cell manufacturing yields and long cycle and calendar life improve. Ultimately, competitiveness will depend on simultaneously meeting requirements for Li plating/stripping CE, Li inventory, electrolyte consumption, manufacturing yield, and cycle and calendar life, rather than achieving the highest Wh/kg alone.

This report organizes anode-free battery development to date by topic, covering academic R&D and industrial efforts led by companies such as Samsung SDI. It provides a systematic understanding of anode-free battery research, development, and future prospects.

Key strengths of this report

① Detailed coverage of anode-free battery fundamentals, research trends, and development status

② Recent R&D results for anode-free ASSBs, Li-metal batteries, Na batteries, and Li–S batteries

③ Detailed coverage of national support programs for anode-free battery development and their technological results

④ In-depth updates and patent analysis of major global anode-free battery developers

Contents	Page
1. Overview of Anode-Free Batteries
1.1 Fundamentals of Secondary Batteries	06
1.1.1 Secondary Battery Fundamentals and Limitations	06
1.2 Anode-Free Battery Systems	07
1.2.1 Concept of Anode-Free Batteries	07
1.2.2 Advantages of Anode-Free Batteries	08
1.2.3 Practical Conditions and Performance Requirements	09
1.3 Challenges of Anode-Free Batteries	10
1.3.1 Irreversible Li Loss	10
1.3.2 Interfacial Degradation	11
1.4 Anode Materials for Anode-Free Batteries	12
1.4.1 Anode Active Materials and Requirements	12
1.5 Strategies for Anode-Free Batteries	13
1.5.1 Anode-Free Batteries for Long Cycle Life	13
1.6 Manufacturing Changes with Anode-Free Technology	14
1.6.1 Potential Elimination of Anode Manufacturing Lines	14
1.6.2 Expanded Role of Cu Foil	15
1.6.3 Importance of Initial Charging	16
1.6.4 Importance of Initial Charge Time and Stack Pressure	17
1.6.5 Electrolyte as the Li Plating Process Medium	18
1.6.6 Cathode as the Li Inventory	19
1.6.7 Separator and Cell Stacking Precision	20
1.6.8 Changes in Cell Thickness and QC Equipment	21
1.6.9 Manufacturing Yield: Importance of First-Plating Yield	22
1.6.10 Changes in Battery Manufacturing Line Layout	23
1.6.11 Changes in Cost Structure and Solid-State Battery Manufacturing	24
1.6.12 Changes in Battery Manufacturing Paradigms	25

2. Degradation Mechanisms of Anode-Free Batteries
2.1 Limited Metal Inventory and High CE Requirements	27
2.1.1 Limited Li Inventory in Anode-Free Cells	27
2.1.2 High CE Requirements for Practical Cells	28
2.1.3 Continuous Li Consumption through SEI Formation	29
2.2 Nonuniform Plating and Dead Li Formation	30
2.2.1 Nonuniform Nucleation on Current Collectors	30
2.2.2 Ion Concentration Gradients and Local Current Density	31
2.2.3 Nonplanar Metal Growth and Increased Surface Area	32
2.2.4 Dead Li Formation and Electrical Isolation	33
2.3 Electrolyte Consumption and Degradation in Practical Cells	34
2.3.1 Electrolyte Decomposition on Reactive Metal Surfaces	34
2.3.2 Accelerated Degradation under Lean-Electrolyte Conditions	35
2.3.3 Challenges in Large-Area, High-Capacity Pouch Cells	36
2.4 Corrosion during Rest	37
2.4.1 Cycling Degradation vs. Degradation during Rest	37
2.4.2 Chemical Corrosion	38
2.4.3 Galvanic Corrosion	39

3. Electrolyte and Interface Design for Anode-Free Batteries
3.1 Solvent Design for Anode-Free Batteries	41
3.1.1 Carbonate-Based Electrolytes	41
3.1.2 Ether-Based Electrolytes	42
3.2 Electrolyte Modification for Anode-Free Batteries	43
3.2.1 Highly Concentrated Electrolytes	43
3.2.2 Localized High-Concentration Electrolytes	46
3.2.3 Salt and Anion Composition Modification	49
3.2.4 Electrolyte Additives	53
3.3 Electrolytes for Next-Generation Anode-Free Batteries	58
3.3.1 Solid and Polymer Electrolytes	58
3.3.2 Flame-Retardant Electrolytes	60
3.4 Artificial SEI and Protective Layer Design	63
3.4.1 Need for Interfacial Protective Layers	63
3.4.2 Inorganic Protective Layers	64
3.4.3 Polymer Protective Layers	66
3.5 Nucleation Control with Lithiophilic Interlayers	68
3.5.1 Li Nucleation Control with Alloying Interlayers	68
3.5.2 Li Nucleation Control with Defect-Rich Carbon	70
3.5.3 Li+ Adsorption Control with Polar Sites	72
3.5.4 Li Nucleation Control with Single-Atom Sites	74
3.5.5 Cu Foam-Based 3D Host Structures	76
3.5.6 Combined Li Nucleation and SEI Control via Interface Design	78

4. Extended Anode-Free Battery Systems
4.1 Solid-Electrolyte-Based Anode-Free Batteries	81
4.1.1 Rationale for Solid Electrolytes	81
4.1.2 Solid Electrolyte Types and Properties	82
4.1.3 Sulfide-Based Anode-Free Solid-State Batteries	83
4.1.4 Oxide-Based Anode-Free Solid-State Batteries	87
4.1.5 Polymer-Based Anode-Free Solid-State Batteries	91
4.1.6 Summary of Solid Electrolyte Challenges	95
4.2 Li2S Cathode-Based Anode-Free Batteries	96
4.2.1 Lithium–Sulfur and Li2S Batteries	96
4.2.2 Li2S-Based Anode-Free Batteries	98
4.2.3 Summary of Li2S Cathode Challenges	103
4.3 Sodium-Based Anode-Free Batteries	104
4.3.1 Sodium Metal Batteries	104
4.3.2 Sodium-Based Anode-Free Batteries	106
4.3.3 Summary of Sodium Metal Battery Challenges	110
4.3.4 Sodium-Based Anode-Free Batteries: CATL’s In-Situ Self-Forming Anode	111

5. National Anode-Free Battery Programs (Projects)
5.1 Anode-Free Battery Support Projects by Country	116
5.1.1 Support Projects by Country	116
5.2 US program(PJT)	118
5.2.1 Anode free Lithium Batteries	118
5.2.2 Anode free Sodium Batteries	121
5.2.3 Anode free All solid Batteries	122
5.3 EU Program(PJT)	124
5.3.1 SOLVE: Gen4b All-Solid-State Battery Development	124
5.3.2 AM4BAT: Gen4b All-Solid-State Battery Manufacturing	131
5.3.3 MSCA - Anode free LIBs	137
5.4 China Programs (Projects)	141
5.4.1 Beyond Traditional Battery Systems	141
5.5 Korea Programs (Projects)	144
5.5.1 National Anode-Free R&D Projects and Programs	144
5.5.2 Current Collectors for Anode-Free and Solid-State Batteries	145
5.5.3 EPIC International Joint Cluster	146
5.5.4 900 Wh/L Sulfide-Based National Project	147
5.5.5 Next-Generation Battery Innovation Research Group (K-BIC)	148
5.5.6 Aerosol-Based Lithiophilic Material Development	150
5.5.7 Core Technologies for High-Efficiency Anode-Free Li Secondary Batteries (1)	152
5.5.8 Core Technologies for High-Efficiency Anode-Free Li Secondary Batteries (2)	156
5.5.9 Ag Precipitation in Li-Argyrodite Electrolytes for Initially Anode-Free Solid-State Batteries	157
5.5.10 Anode-Free Li Batteries via Cu Surface Modification and Molten Li Thinning	159

6. Anode-Free Battery Development and Patent Analysis
6.1 SDI	161
6.1.1 SDI Anode-Free Concept and Core Technology	161
6.1.2 Key Patent Analysis	162
6.1.3 Evolution of SDI Anode-Free Technology and SolidStack / Technological Competitiveness	165
6.2 LG ES	167
6.2.1 Basic Architecture of LG ES Anode-Free Technology	167
6.2.2 Key Technology: LPM Coating and Other Approaches	168
6.2.3 Integration with Solid-State Batteries and Dry Electrodes	172
6.3 SK On	174
6.3.1 SK On Anode-Free Technology Development Direction	174
6.3.2 SK On Key Publications and Patents	175
6.3.3 PEMA-Based Ultrathin Ag Functional Layers	176
6.4 Hyundai Motor	179
6.4.1 Basic Architecture of Hyundai Motor Anode-Free Technology	179
6.4.2 Key Technology: Metal Fluoride Conversion Layers and Other Approaches	180
6.4.3 Key Patents: Uniform Li Deposition and More	182
6.5 CATL	186
6.5.1 CATL Anode-Free Technology Strategy	186
6.5.2 Li and Na Anode-Free Patent Analysis	187
6.5.3 CATL Core Anode-Free Technologies	189
6.6 BYD	192
6.6.1 BYD Core Anode-Free Architecture	192
6.6.2 Cathode-Side Li Inventory Strategy	195
6.6.3 BYD Key Anode-Free Patents and Technologies	196
6.7 SVOLT	197
6.7.1 Anode-Free Development and Key Patents	197
6.7.2 Key Patent Analysis	198
6.7.3 SVOLT Anode-Free Architecture	202
6.8 Panasonic	203
6.8.1 Anode-Free Development Targets and Roadmap	203
6.8.2 Key Patent Analysis: Stabilizing Li Metal Deposition	204
6.8.3 Separator / Current Collector / Electrolyte Development	205
6.9 QuantumScape	209
6.9.1 Anode-Free Architecture and Ceramic Separators	209
6.9.2 Separator Production Process: Cobra	211
6.9.3 Key Patent Analysis: Solid Electrolytes / Surface Defects	213
6.10 TeraWatt Technology	216
6.10.1 TeraWatt Anode-Free Technology	216
6.10.2 Key Patent Analysis: Interfacial Adhesion Layers and More	217
6.10.3 Surface Coatings and Composite Current Collectors	220
6.11 SES AI	222
6.11.1 Anode-Free Technology and Initial Architecture	222
6.11.2 Highly Concentrated Solvent-in-Salt Electrolytes	223
6.12 Ampcera	225
6.12.1 Core Technology: Li Dendrite-Suppressing Separators	225
6.12.2 Solid Electrolyte Membrane Patent Analysis	226
6.13 ONE(Our Next Energy)	227
6.13.1 ONE Anode-Free Technology Concept	227
6.13.2 Gemini Dual-Chemistry Strategy	229
6.13.3 Key Patent Analysis: Prelithiation and More	231
6.14 POSCO FM / Kumho Petrochemical / BEI	233
6.14.1 Basic Architecture of the Three-Company Collaboration	233
6.14.2 Company Roles: Cathodes / CNTs / Cell Manufacturing	234
6.14.3 Key Challenges for Each Company	237
6.15 Ganfeng Lithium	239
6.15.1 Ganfeng Anodeless Technology Development	239
6.16 Summary of Anode-Free Development by Company (1–3)	240

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