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Next-generation lithium batteries: Science and technology

Dendrites, shuttles and the chemistry still stopping them

What this tab covers The physics and chemistry: how the energy is stored, which materials it needs (scarcity, toxicity, recyclability) and what makes it age.

Solid-state, lithium-sulphur and lithium-air cells aim to beat today's lithium-ion on energy per kilogram or safety. Only semi-solid-state cells are on sale; the rest are prototypes or lab work, with life and manufacturing problems still unsolved.

Mechanism

Mixed

Solid-state batteries keep intercalation chemistry but replace the liquid electrolyte with a solid one (polymer, oxide or sulphide), which could allow a pure lithium-metal anode. Semi-solid polymer cells are already commercial but must run at about 60 to 90 C so the polymer softens enough to conduct. Lithium-sulphur is a conversion battery: lithium reacts with a sulphur cathode to form new compounds rather than slotting into a host, which gives high theoretical energy per kilogram. Lithium-air goes further, reacting lithium with oxygen drawn from air, so the cathode is mostly empty porous carbon. CATL announced a 'condensed' cell of up to 500 Wh/kg in 2023 (a company claim), against 150 to 300 Wh/kg for mass-produced lithium-ion. Lithium-sulphur's theoretical ceiling is about 2,600 Wh/kg; Li-S Energy reported 498 Wh/kg on first discharge and 456 Wh/kg after formation cycling in a 10 Ah semi-solid-state pouch cell in 2024 (a company claim, with no cycle life given). A 2023 Argonne and Illinois Tech lithium-air cell with a solid electrolyte forms lithium oxide and could, according to its developers, reach about 1,200 Wh/kg, roughly four times lithium-ion, with further development; this is a projection, not a measured cell value.128913

Operating temperature, commercial semi-solid polymer cells about 60-90 C1 CATL condensed cell (2023 company claim) 500 Wh/kg2 Mass-produced lithium-ion today 150-300 Wh/kg2 Lithium-sulphur theoretical energy density about 2,600 Wh/kg8 Li-S Energy pouch cell (2024 company claim) 498 Wh/kg first discharge, 456 Wh/kg after formation9 Lithium-air projected potential (Argonne/Illinois Tech) up to 1,200 Wh/kg13

Material scarcity and toxicity

Mixed

Solid-state cells still need lithium, and lithium-metal anodes may need more of it per kWh; China refines most energy minerals, about 70% on average across the strategic minerals the IEA tracks. Lithium-sulphur avoids cobalt and nickel and uses sulphur, an abundant by-product of oil and gas refining. Lithium-air also avoids transition-metal cathodes. Sulphide solid electrolytes can give off toxic hydrogen sulphide if exposed to moisture, so production needs dry rooms. Lyten says its cells need no nickel, cobalt, manganese or graphite (a company claim).711

China average refining share, strategic energy minerals around 70%7

Degradation and ageing

Unfavourable

In solid-state cells, lithium can still grow needle-like dendrites through cracks in the electrolyte, and the solid layers lose contact as electrodes swell and shrink, which is why packs need high stack pressure. Lithium-sulphur suffers from the 'shuttle' effect, in which dissolved polysulphides drift between electrodes; a 2022 study of a 400 Wh/kg pouch cell found polysulphides left in the electrolyte and severe change to the lithium-metal anode, and blamed rapid loss of active material for short life. Developers' claims remain targets: Zeta Energy said in 2023 it was on track for 450 Wh/kg and over 1,000 cycles by a 2025 launch, but no independently verified cycle count was found. The best lithium-air result is at least 1,000 cycles in the 2023 Argonne laboratory cell (published in Science), but reviews still list practical capacity, efficiency and cycle life as unsolved.8101314

Lithium-air cycles demonstrated (lab, 2023) at least 1,00013 Zeta Energy lithium-sulphur target over 1,000 cycles, 450 Wh/kg (2023 claim)10

Variants compared19101113

VariantStatus (2026)Main promiseMain barrierNamed developers
Semi-solid-stateCommercialBetter safetyMust run warm (about 60-90 C)Not named by the IEA
All-solid-statePrototype; first cars planned 2027-2028Energy density and safetyComplex, costly manufacturing; stack pressureToyota, BYD, Samsung, QuantumScape, Factorial
Lithium-sulphurPilot cells; Lyten announced a 10 GWh Nevada plant (Phase 1 targeted for 2027) in 2024No cobalt, nickel or graphite; lightPolysulphide shuttle, lithium anode wear, short lifeLyten, Li-S Energy, Zeta Energy
Lithium-airLaboratory (1,000 cycles in a 2023 lab cell)Up to 1,200 Wh/kg potentialEfficiency, capacity and lifeArgonne National Laboratory, Illinois Institute of Technology

Sources

  1. Global EV Outlook 2026: Electric vehicle batteries International Energy Agency, 2026
  2. Sodium-ion batteries: Technology brief IRENA, 2025
  3. Diversification is the cornerstone of energy security, yet critical minerals are moving in the opposite direction (Global Critical Minerals Outlook 2025) International Energy Agency, 2025
  4. Evaluation on a 400 Wh/kg lithium-sulfur pouch cell (Ye et al., Journal of Energy Chemistry 66, 24-29) Journal of Energy Chemistry, 2022
  5. Li-S Energy achieves 498 Wh/kg lithium-sulfur cell performance (ASX announcement) (company announcement) Li-S Energy Ltd, 2024
  6. Zeta Energy announces graphite-free and cobalt-free batteries on target to reach 450 Wh/kg and over one thousand cycles by 2025 (company press release) Zeta Energy (PR Newswire), 2023
  7. Lyten plans first lithium-sulfur battery gigafactory in Nevada ESS News, 2024
  8. Innovative Lithium-Air Battery Design Poised to Increase Energy Storage (Kondori et al., Science 379, 499-505, 2023) US Department of Energy, Office of Science, 2023
  9. Advances and challenges in lithium-air batteries (Tan et al., Applied Energy 204, 780-806) Applied Energy, 2017