Physics / mechanism
Electrochemical energy storage converts chemical potential to electrical work via redox reactions at anode/cathode interfaces separated by an electrolyte. Key parameters: energy density (Wh/kg or Wh/L), power density (W/kg), cycle life, coulombic efficiency, and C-rate capability. Lithium-ion dominates at 250–300 Wh/kg cell-level; solid-state targets 400–500 Wh/kg with improved safety by replacing liquid electrolyte with ceramic or polymer. Flow batteries (vanadium, iron-air) decouple energy and power, suiting grid-scale. Sodium-ion is emerging for cost-sensitive stationary applications. Lifetime degradation mechanisms — lithium plating, SEI growth, cathode cracking — remain the core engineering constraint.
Competitive landscape
Competing and adjacent approaches: supercapacitors offer 10–100× higher power density but 10–50× lower energy density, suited for buffer/regen applications. Hydrogen storage (compressed, liquid, solid-state metal hydride) competes at long-duration grid and heavy transport. Mechanical storage — pumped hydro, compressed air, flywheels — remains dominant in installed GWh terms. At materials level, cathode chemistry (NMC, LFP, NCA, LMFP) and anode choice (graphite vs. silicon vs. lithium metal) are the primary differentiation axes. Electrolyte innovation — sulfide vs. oxide solid electrolytes, ionic liquids — is where most deep-tech IP sits today.
| Technology | Energy Density | Best Use Case |
|---|---|---|
| Li-ion (NMC) | 250–300 Wh/kg | EV, portable |
| Vanadium flow | 20–40 Wh/kg | Long-duration grid |
| Solid-state Li | 400–500 Wh/kg (projected) | EV, aerospace |
Companies using
Connected ideas
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Frontier (open questions)
- To be added.