How KIB Compares
‍to Every Other Chemistry in the Room

The definitive 108-page KIB review from Komaba lab, Tokyo University of Science — one of the two or three most cited groups in K-ion battery science globally. Published in Chemical Reviews (IF ~72). Key data: K⁺ Stokes radius 3.6 Å is the smallest of all alkali ions, directly supporting fast electrolyte transport; K⁺/K standard potential −2.93V enables higher cell voltage than Na-ion; K crustal abundance ~2.6% vs Li ~0.002% (1,300× ratio); Al current collector works at both anode and cathode, eliminating the Cu foil required by Li-ion. Also identifies the three PBA degradation mechanisms — Mn dissolution, vacancy formation, water side reactions — explaining why defect-free synthesis is required for long cycle life. Supports Rate Capability, Energy Density, Cycle Life, Safety, TCO, and Supply Chain claims.

Demonstrates defect-free KMF cathode via EDTA-chelated synthesis, achieving 7,800-cycle life at 3.33C (80% retention) — the literature ceiling for this chemistry class. Full cell with graphite anode: 331.5 Wh/kg at 3.58V average discharge, higher voltage than LFP||Graphite (3.2V). Rate performance: 58% capacity at 6.67C. Notably, defect-free KMF produces negligible HCN vs defective material, confirming that synthesis quality is critical for PBA safety. Beihang University (top-9 China). Supports Cycle Life and Rate Capability claims; the 7,800-cycle figure is the literature maximum — Group1's publicly demonstrated specification is 1,000 cycles (Beyond Lithium Conference, ORNL, August 2024).

First rigorous DFN full-cell model of a KIB in commercial cell format (LG M50 geometry), from Pasta lab at Oxford — the leading non-UT group on K-ion science. Key kinetics finding: KMF exchange current density j0 is slightly better than LFP at the electrode level; with optimised electrolyte, KIB matches LFP at 5C (35% vs 37% accessible capacity). Critical limitation documented: current KFSI:TEP electrolyte delivers only 8% accessible capacity at 5C due to high viscosity — the electrolyte is the commercial bottleneck, not the electrode materials. Stack-level energy comparison: KIB gravimetric energy is 1% better than LFP but volumetric is 24% lower due to KMF bulk density (2.22 vs 3.45 g cm⁻³). The most important independent quantification of the KIB vs LFP rate and energy tradeoffs available in the literature. Open access.

Comprehensive outlook on K-ion batteries from Pasta lab (Oxford), establishing the physical basis for KIB's rate advantage. Key data: K⁺ Stokes radius 3.6 Å is the smallest of all alkali ions; K⁺-graphite solid-state diffusion coefficient 2.0×10⁻¹⁰ m²/s vs Li⁺ 1.5×10⁻¹⁵ m²/s — five orders of magnitude faster. Graphite-K intercalation potential stays above K-metal plating potential, reducing dendrite risk. Supports Rate Capability and Safety claims.

Demonstrates a PBA-cathode KIB operating at 60°C with good cycling stability and rate capability — the most direct published evidence for KIB high-temperature performance. Key data: 3.6V cell, 381 Wh/kg, 89% retention after 820 cycles at room temperature; at 50–60°C, higher specific capacity and lower overpotential than room temperature due to enhanced K-ion kinetics. Stanford/Tsinghua/Taiwan, Hongjie Dai lab. Note: uses a cobalt-doped PBA composition with ionic liquid electrolyte rather than Group1's KPW with carbonate — same structural class, different chemistry. Supports High-Temp Performance claim.

Identifies self-discharge in high-voltage K-ion cathodes as driven by electrolyte degradation above ~4.7V vs K/K⁺ — an electrolyte-side reaction, not structural instability of the cathode itself. From ICMCB Bordeaux / RS2E (French national electrochemical storage network), using synchrotron XRD. Key relevance: KPW operates at ~3.7–4.0V vs K/K⁺, approximately 0.7–1.0V below this self-discharge onset threshold. Provides mechanistic support for KPW's low self-discharge claim. Supports Self-Discharge score.

Comprehensive PBA review covering Na-, K-, and multivalent-ion cathode materials. Shanghai University / University of Western Ontario. Key findings: open 3D PBA channel structure is intrinsically compatible with long cycle life when defects and water content are controlled; defect-poor synthesis via chelating agents (citrate, EDTA) is the established route to high-performance PBAs — the same principle underlying Group1's KPW synthesis. Documents that PBA synthesis routes are scalable and use earth-abundant precursors. Supports Cycle Life and TCO claims.

Bazant's flagship theoretical paper (~620 citations), MIT. Presents a unified nonequilibrium thermodynamic theory of charge transfer and intercalation kinetics for phase-separating electrode materials, validated empirically against LFP. Key finding: phase separation in LFP nanoparticles is suppressed under applied current — the intercalation wave propagates as a reaction-limited front, explaining LFP's high rate capability despite two-phase equilibrium. KMF (K₂Mn[Fe(CN)₆]) is also a phase-separating intercalation cathode in the same materials class; the measured j0,KMF from Dhir et al. [11] being comparable to LFP's j0 is consistent with this theoretical framework. Provides the physics language underlying Rate Capability claims for both LFP and KIB.

Stanford/SLAC DOE-funded analysis modeling 6,048 scenarios for Na-ion price competitiveness vs LFP. Nature Energy (IF ~67) — the highest-impact journal in this reference list. Key finding: pre-2030 price advantage over LFP is challenging; under baseline conditions, price parity arrives ~2035 and price advantage ~2047. 2,522 of 6,048 scenarios produce no Na-ion price advantage before 2050. Hard carbon anode identified as a structural cost driver — low tap density and slopey voltage profile impose materials intensity penalties; may require >400 mAh/g improvements or replacement to compete long-term. Cell modeling puts 2024 baseline Na-ion at 134 Wh/kg / 272 Wh/L. Supports Na-ion TCO and Energy Density scores, and indirectly strengthens KIB supply chain argument: the three supply chains that determine Na-ion competitiveness (lithium, graphite, nickel) are the three KIB structurally avoids.

The authoritative Na-ion battery review from Yang-Kook Sun's lab, a world-leading Na-ion research group. Published in Chemical Society Reviews (IF ~46). Covers Na-ion cathode materials, anodes, electrolytes, and system-level performance. Used as the general Na-ion reference anchoring the Na-ion chemistry context on this chart. Supports Na-ion Energy Density, Rate Capability, and Cycle Life scores.

Comparative study of graphite electrodes for Li, Na, and K batteries. Seoul National University; Kisuk Kang, one of the most cited battery scientists globally (now also at MIT). Key finding: Na⁺ cannot intercalate into graphite as a bare ion under standard battery conditions — K⁺ forms stable KC₈ reversibly while Na does not. Na-ion batteries therefore require hard carbon anode, which carries lower volumetric density and higher cost than graphite. Supports the Energy Density and TCO score differential between KIB and Na-ion.

DFT first-principles study from Japan Fine Ceramics Center showing Na-graphite intercalation compound (GIC) formation energies are positive — thermodynamically unstable — at all intercalation stages. Only sodium among the alkali metals cannot form stable GICs; K-GIC is more stable than even Li-GIC. Provides the theoretical basis for why Na-ion requires hard carbon anode while K-ion uses standard graphite. The finding has been independently confirmed by multiple groups. Supports Na-ion Energy Density and TCO scores; provides theoretical backing for KIB's graphite anode advantage.

Definitive mechanistic reference for alkaline zinc electrode failure modes, from Jun Lu's group at Argonne National Laboratory (DOE/NSF funded). ACS Energy Letters (IF ~19). Documents the three fundamental electrochemical constraints of alkaline Zn anodes: ZnO/Zn(OH)₂ passivation blocking active material, dendritic zinc growth limiting cycle life, and hydrogen evolution reaction (HER) as a parasitic process that directly causes self-discharge by oxidizing the zinc anode at rest. These are structural constraints of the alkaline zinc system, not engineering failures — directly applicable to Ni-Zn batteries which use the same anode chemistry. Supports Ni-Zn Cycle Life and Self-Discharge scores.

Comprehensive reliability review of Ni-Zn battery systems from CAiRS Hong Kong / Hong Kong Polytechnic University / NTNU Norway. EcoMat (Wiley), open access. Covers degradation mechanisms and improvement strategies across the full system. Key findings: zinc dendrite formation, anode deformation, and passivation are identified as fundamental constraints on cycle life not fully resolved by current engineering; self-discharge driven by zinc anode corrosion in alkaline electrolyte; thermal management is a documented reliability challenge. Confirms aqueous alkaline electrolyte is inherently non-flammable — Ni-Zn's strongest differentiator. Supports Ni-Zn Cycle Life, Self-Discharge, High-Temp, and Safety scores.

Comprehensive review of lead battery technology for utility and stationary energy storage, comparing directly with Li-ion and other chemistries. Open access. Covers cell construction, performance characteristics, failure modes, and real-world deployments including UPS and grid applications. Key findings: typical VRLA energy density 30–50 Wh/kg; AGM cells are the dominant design for UPS and standby due to predictable charge regimes; replacement cycles of 3–5 years in float service drive TCO significantly higher than upfront cost suggests; H₂ evolution during overcharge requires ventilation. The primary academic reference for lead-acid performance characteristics on this chart. Supports Energy Density, Cycle Life, TCO, and Safety scores.

The largest field reliability study of stationary VRLA batteries available in the public literature — DOE Energy Storage Systems Program, conducted by Sandia National Laboratories. Survey of over 700,000 VRLA cells across US stationary applications. Key findings: 42% of cells operated 5+ years before replacement; 25% were never replaced — but a significant portion underperformed nameplate due to positive grid corrosion, electrolyte stratification, and thermal stress. Temperature is identified as the dominant environmental factor for VRLA life, directly relevant to data center rack conditions. AGM cells are confirmed as the dominant design for UPS and standby — establishing the incumbent technology Group1 is displacing. Supports Lead-Acid Cycle Life and High-Temp scores.

Invited talk by Shinichi Komaba (Tokyo University of Science) — the world's most cited KIB scientist — to the EU Battery2030+ Excellence Seminar, March 2024. Battery2030+ coordinates 100+ European institutions and is the EU's flagship battery research initiative. Title: Na-ion and K-ion chemistry for sustainable battery. Non-peer-reviewed but cited as an authority signal: the field's leading academic voice presenting K-ion as a viable chemistry direction to Europe's premier battery strategy program.

Manthiram presentation noting that PBA cathodes can release HCN and cyanogens at elevated temperatures — a relevant safety nuance for Na-ion PBA variants such as Altris. KPW's manganese substitution addresses this pathway, meaning Na-ion PBA and KPW are not equivalent from a safety standpoint despite both using the PBA framework.

Li-ion batteries classified as a new fire hazard category specifically in AI data centers. Trade publication, not peer-reviewed — cited for regulatory and market context. Establishes why Safety is increasingly a procurement gating criterion for hyperscale UPS buyers. KIB (oxygen-free cathode) and Ni-Zn (aqueous electrolyte) avoid this classification through different mechanisms.

Public product announcement for the world's first KIB in standard 18650 format, presented at the 14th Annual Beyond Lithium Conference, Oak Ridge National Laboratory. Specifications: 3.7V nominal, standard graphite anode, 1,000 cycles demonstrated. The >20C discharge rate is a product target, not an independently validated specification. This is a public press release (not peer-reviewed) — cited as the primary public source for Group1's commercial specification claims.

Public announcement of the world's first potassium-ion battery in standard 18650 cylindrical format, presented at the 14th Annual Beyond Lithium Conference at Oak Ridge National Laboratory. Key specifications publicly disclosed: 3.7V nominal, 18650 format (drop-in compatible with Li-ion), 1,000-cycle demonstrated performance.

MPSC mines potassium at $1.2B DOE-backed US Potash Project. Group1 MOU includes KIB UPS installation. Complete domestic loop: K mined → cells made → batteries deployed at source.

LFP upstream ~70%+ China-controlled. Primary basis for LFP Supply Chain Sovereignty score of 3.

China dominates cathode, anode, electrolyte, separator, and cell manufacturing globally.

Every 10°C above 25°C approximately halves lead-acid calendar life. Data centers at 35–40°C reduce lead-acid life to 1–2 years. Basis for Lead-Acid High-Temp score of 3.

Aqueous above 40°C: accelerated water evaporation, electrolyte concentration shifts, corrosion. Basis for Ni-Zn High-Temp score of 4.

Aqueous electrolyte safety claim is legitimate and their strongest differentiator. Note: Natron Energy (similar aqueous PB chemistry for data center UPS) ceased all operations September 2025.

~15–20%/month self-discharge is intrinsic to NiOOH instability in aqueous electrolyte — not an engineering fix. Basis for Ni-Zn Self-Discharge score of 3.