Scalable and sustainable manufacturing of thick electrode films with high energy and power density is critical for large-scale electrochemical energy storages (EESs) in transportation and stationary electric grid applications. Two-dimensional (2D) nanomaterials have become the predominant choice for electrode material when pursuing high energy and power densities in EESs due to their large surface area to volume ratios and lack of solid-state diffusion. However, traditional electrode fabrication methods often lead to restacking of 2D nanomaterials, which limits ion transport in thick films, resulting in systems with highly thickness-dependent electrochemical performance. Vertical alignment of 2D flakes enabling directional ion transport is perferred. So far, only limited success has been reported, and mitigating performance losses remains a major challenge when the film thickness of 2D nanomaterials exceeds 100 µm. Here we demonstrate thickness-independent EES in vertically aligned 2D titanium carbide (Ti3C2TX) from the MXene family by mechanical shearing of a discotic lamellar liquid crystal (LC) phase of Ti3C2TX. The resulting electrode films show exceptional rate handling and nearly thickness-independent performance up to 200 µm. The self-assembly approach developed here is scalable and can be extended to other systems involving directional transport.

Thickness independent capacitance of vertically aligned liquid crystalline MXenes

256th National Meeting (2018)

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