A lithium-ion cell bill of materials (BOM) is dominated by eight line items: cathode active material, anode active material, separator, electrolyte, two current collectors (Al foil for cathode, Cu foil for anode), tabs, casing, and a battery management system / protection board [S2][S4]. Of these, the cathode and anode chemistries set the cell's nominal voltage between 2.3 V (Li4Ti5O12) and 3.85 V (high-nickel NCA), and govern specific energy, which for commercial cells runs 160-300 Wh/kg and up to 450 Wh/kg in specialty silicon-anode builds [S2].
Argonne National Laboratory's GREET model maintains updated cathode-specific BOMs for LMO, LFP, NMC111, NMC622, and NCA cells, covering precursor salts, binder, conductive carbon, and foil thickness at the gram-per-cell level [S1]. Buyers specifying cells for EV, BESS, or industrial packs should treat that GREET BOM dataset as the reference for upstream mass-allocation, since the precursor mix (Ni:Co:Mn ratio) directly changes the cell's cobalt exposure and the bill's $/kWh sensitivity [S1].
Cathode active material: LFP vs NMC vs NCA vs LCO
Cathode chemistry is the single largest determinant of cell cost, thermal behaviour, and cycle life, and four families dominate commercial production [S2][S4]. Lithium iron phosphate (LFP) offers high safety and longevity with moderate energy density and is the dominant cathode in Chinese stationary storage and entry-level EV packs; lithium nickel manganese cobalt oxide (NMC) balances high energy density with moderate safety and is the workhorse for European and North American EVs; lithium cobalt oxide (LCO) retains the highest volumetric energy density for consumer electronics at the price of moderate safety; lithium nickel cobalt aluminum oxide (NCA) extends nickel content for higher specific energy at a thermal-stability cost [S3][S4].
For spec-driven comparison, NMC and NCA win on energy density per kilogram, LFP wins on cycle life and thermal runaway margin, and LCO remains the default for thin consumer cells where volumetric Wh/L matters more than $/kWh [S3][S4]. Argonne's cathode-keyed BOMs let a buyer model NMC811 vs NMC622 cost deltas at the precursor level rather than at the finished-cell level, which is where the largest material-saving levers sit [S1].
Anode active material: graphite, silicon blends, and Li4Ti5O12
Graphite is the most common anode material, valued for stable structure, low cost, and reliable cycling, and serves as the baseline for nearly all commercial Li-ion cells [S3][S5]. Silicon-based anodes are the active drop-in upgrade, with published sources indicating a 20-40% energy-density uplift versus graphite-only anodes, at the price of larger volume change during lithiation that must be managed with binder and nano-structuring [S4].
Lithium titanate (Li4Ti5O12, LTO) is a niche anode used where extreme cycle life and a 2.3 V nominal cell voltage are acceptable, commonly in grid and heavy-duty applications [S2]. Copper foil functions as the anode current collector, and its thickness (commonly 8-12 micrometres in EV cells) is itself a spec line item in the BOM that affects both energy density per litre and tab-welding process windows [S3]. Buyers chasing a 2026 BOM should track silicon-graphite blend ratios, since the silicon share is the fastest-moving variable in the anode line item.
Separator, electrolyte, and the safety envelope
The separator is a microporous polyolefin film (typically PE, PP, or a PP/PE/PP trilayer) that physically isolates the two electrodes while allowing lithium-ion conduction through the electrolyte, and its shutdown behaviour above ~130 degree C is the first line of defence against thermal runaway [S2][S4]. Electrolyte is a lithium salt (commonly LiPF6) dissolved in organic carbonates such as EC, DMC, and EMC, and it can be liquid, gel, or solid; solid-state electrolyte builds target higher energy density and the removal of flammable liquid solvent [S4][S7].
For procurement, the separator and electrolyte line items together typically account for a smaller share of the BOM than cathode active material but carry disproportionate qualification effort, because a separator failure (pinhole, shutdown failure) is a recall trigger rather than a performance issue [S6]. Cell builders digitizing their BOM in 2026 cite recall traceability and per-batch quality as the principal drivers, which makes separator lot-level traceability a hard requirement rather than a nice-to-have [S6].
Current collectors, tabs, casing, and the protection PCB
Aluminium foil (typically 15-20 micrometres) is the cathode-side current collector, copper foil (8-12 micrometres) is the anode-side, and both must be specified for purity, thickness tolerance, and surface treatment to keep interfacial resistance within the cell's internal-resistance budget [S2][S3]. Tabs connect the electrode foils to the external terminals and are usually nickel- or nickel-plated for the cathode side and bare or tin-plated copper for the anode side; tab geometry is a non-trivial BOM line because it sets the maximum continuous current the cell can deliver without overheating.
Casing materials split into three families: steel prismatic (cost-optimised for ESS), aluminium prismatic (common in EV mid-format), and aluminium laminate (pouch cells, highest packaging efficiency) [S4]. The battery management system / protection PCB is the final BOM item, providing over-voltage, under-voltage, over-current, and short-circuit cut-off, and it is mandatory for any multi-cell pack shipped into the EU under IEC 62133 and UN 38.3 transport testing [S2][S4].
BOM cost levers, supply chain, and 2026 sourcing signals
On a mass basis the cathode active material is the single heaviest line item, followed by anode, electrolyte, separator, and collectors, but on a cost basis the ordering reshuffles because of precursor salt pricing for nickel, cobalt, and lithium [S1][S4]. The 2026 procurement signal is the decoupling of LFP and NMC supply chains: LFP is dominated by Chinese cell makers with iron and phosphate as low-volatility inputs, while NMC and NCA remain exposed to nickel and cobalt price swings, which is why cobalt-sulfate shortlists are part of any NMC BOM review (cobalt sulfate supplier shortlist) [S1].
Recycling is moving from a sustainability story to a BOM line item, with commercial hydrometallurgical routes now claiming 95% lithium recovery from end-of-life cells and feeding recycled nickel and cobalt sulfates back into NMC precursor lines [S3]. A defensible 2026 BOM therefore needs a recycled-content column, a precursor-purity column, and a tariff/duty column alongside mass and cost, otherwise the cell-level price comparison is not apples-to-apples. For lithium sourcing specifically, the 2026 spec-driven playbook is laid out in the lithium procurement guide, and any reader building a battery BOM should pair that reference with the cobalt shortlist to close the cathode precursor loop (lithium procurement strategy).
For the relevant spec sheets and selection criteria, see shaft key, construction machinery and equipment, and lamps and light fittings.
Related analysis: Cobalt sulfate supplier shortlist: spec grades, packaging, and regional lead times.