Fabrication of a Novel, Multidimensional, 2.5D All-Solid-State Lithium-Ion Battery

Abstract

The limitations of current microbattery designs is best highlighted by the restricted electrochemical performance of planar cells stemming from their long diffusion path lengths, or by the fabrication and material constraints of recent, novel 3D-electrode architectures. Herein, the fabrication and properties of a multidimensional, high areal-capacity, 2.5D battery are described as means to address the limitations of planar and 3D-electrode designs. Our 2.5D battery, composed of a 3D LiFePO4 array and a planar Li anode, provides a way to achieve high energy densities, while utilization of a high ionic conductivity, solution-processed ionogel electrolyte enables high power densities (4.1 mWh cm-2 at 2.8 mW cm-2). This 2.5D design exhibits improved or comparable energy and power densities to the best 3D batteries in literature, while simplifying the fabrication process, eliminating the liquid electrolyte, and facilitating an easily customizable battery. The exemplary performance and simple fabrication process of the 2.5D design, possible because of the ionogel electrolyte, presents a promising direction for the integration of energy-storage devices into on-chip and microelectronic applications that is impractical with current high-performance 3D-battery designs. Figure 1