Advance in Structural Battery Technology: Integrating Lithium Titanate to Overcome Limitation of Graphite in Carbon Fabric Composite Structural Batteries

Structural batteries based on woven carbon fabrics are typically established on lithium ion phosphate (LFP) and graphite. While this method proved viable from the manufacturing perspective, the resulting structural batteries exhibited suboptimal electrochemical performance. This underperformance is primarily attributed to the electrochemical interference between the graphite coating and the underlying carbon fibers, where lithium ions can partially intercalate into the fibers' turbostratic graphitic structure. This parasitic reaction alters the anode's effective capacity and accelerates degradation, ultimately limiting the battery's overall performance. To address this issue, the present work replaces graphite with lithium titanate (LTO) to eliminate such interference and enhance the electrochemical stability of the structural battery. Specifically, graphite is replaced with LTO, a material known for its high stability and superior electrochemical properties, to produce a fabric anode. The lithium titanate would not interfere with carbon fibers, so the capacity of the structural batteries can be significantly improved. LTO also possesses several other advantages, such as a stable voltage plateau, low volume expansion during charge/discharge cycles and excellent cycle life, all of which are critical for maintaining the structural integrity and longevity of the battery. A liquid electrolyte is adopted in this proof-of-concept study to ensure stable electrochemical performance; the structural functionality is achieved through the carbon-fabric-reinforced encapsulation layers, demonstrating the material-level integration of mechanical and energy-storage functions.

Highlights:
- LTO replaces graphite, removing parasitic effects with carbon fabric.
- Electrochemical performance improved in LFP/LTO structural battery design.
- Spray deposition enables precise mass loading of both electrodes.
- Achievement of high electrochemical and mechanical performance.