Molecular Engineering of Sustainable Functional Materials for Zinc Ion Battery and Lithium Ion Battery

Licentiate thesis, 2026

Electrification places distinct demands on energy storage, from high-energy-density electric vehicles to large-scale grid storage, where cost, safety, and resource availability are critical. Silicon anodes offer a route toward higher-energy-density lithium-ion batteries (LIBs), while aqueous zinc-ion batteries (AZIBs) are an attractive alternative for safe, low-cost grid storage. Yet both face a common challenge: instability at the electrode–electrolyte interface. This thesis addresses these instabilities through molecular engineering of functional interfaces tailored to each system.

For LIBs, a water-processable multi-functional binder was developed by integrating surface-anchoring, network-forming, and ion-coordinating functionalities within a bio-sourced polymer architecture. Copolymerization overcame the molar-mass limitation of bio-derived binders, giving adhesion comparable to commercial poly(acrylic acid) (PAA). The functional groups provide anchoring points to the silicon surface, adaptive hydrogen-bonded network that maintained electrode integrity during volume changes, and facilitating Li⁺ transport. Their synergy delivered high initial coulombic efficiency, improved capacity retention and rate capability relative to PAA, and reduced electrode expansion.

For AZIBs, a hydrogen bond network was constructed on both the MnO₂ cathode and Zn anode via developed approaches specific for each surface. The confined network regulates interfacial proton transport, water organization, and acid–base buffering, suppressing proton-induced side reactions, hydrogen evolution, corrosion, and dendrites. This enabled 617 mAh g⁻¹ at 0.05 A g⁻¹, a Zn symmetric-cell lifetime exceeding 1000 h, and 83% capacity retention over 700 cycles at 3 A g⁻¹ in dual-coated full cells.

Together, these studies establish molecularly engineered interfaces as a versatile route toward durable, sustainable energy storage.