Solid-State / Solid-Liquid Electrolyte Li-Ion Battery Innovation & Patent Review

• Company Chapter – Maxell – Japan

  Version: 2026-09-03, for paid subscribers
• Technology Assessment: Maxell already sells sulfide all-solid-state cells in volume production – a position few developers hold. The chapter examines how an architecture carrying current collection and stack compliance inside the pressed electrode body positions against higher-capacity negative electrodes, why holding interfacial contact without external stack pressure remains the central scale-up question, and how public statements align with what the patent portfolio reveals about development priorities.
  Product Development Pathway
  (5 R&D Concepts)

  Two-stage pressing of pre-densified composite granules – splitting densification across successive steps so electrode density is retained as the pressed area grows, without higher-pressure equipment. Bilayer solid electrolyte sheet pairing a lithium-reactive layer with an argyrodite conduction layer, arresting dendrite propagation inside the separator rather than at the negative electrode interface. Further concepts address volume-change accommodation at high-capacity negative electrodes, interfacial stability where cathode potentials sit beyond the electrolyte window, compliance layers that hold contact without an external stack fixture, and processing routes that keep those layers compatible with existing electrode manufacturing lines.
  Key synergies between R&D concepts: A pressed-body process architecture that every material concept reaches the cell through – densification, interfacial stabilization and volume-change compliance advancing together toward the electrode areas and capacities a well-rounded product launch requires.
• Document size: ≈5,000 words, 6 images, 1 adjacent Excel file (list of patent families with AI-based summaries)

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