Nanoimprinting of Woodpile Electrodes for 3D Lithium-Ion Microbatteries with Both High Capacity and Power

Thursday, 1 June 2017: 17:36
Grand Salon C - Section 13 (Hilton New Orleans Riverside)
W. Li (University of Massachusetts at Amherst), Y. Zhou (University of Massachusetts Amherst), I. Howell, Y. Gai (University of Massachusetts at Amherst), K. R. Carter, and J. J. Watkins (University of Massachusetts Amherst)
The trend of device downscaling drives the corresponding need for power source miniaturization. With footprint area being the determinant form factor for on-chip battery systems, enhancement of areal energy and power density is urgently needed. Due to the 2D configuration limit, it is impractical for a conventional thin film battery to possess high capacity and power simultaneously.

Here, we show that a novel 3D woodpile electrode, made from TiO2 nanoparticles using solvent-assisted nanoimprint lithography (NIL), can remarkably enhance both the capacity and power of a lithium-ion battery (LIB). With the convenience of sequential imprinting, woodpile electrodes of different heights are readily made in a “stack-up” manner, resulting in a proportional increase of capacity, which is hard to achieve in thin film batteries. Little evidence of specific capacity decrease was observed as the structure height increased by stacking additional layers. These 3D electrodes boast superior rate performance with 1.5- to 6-fold improvement of the specific capacity (compared to 2D counterpart) during fast cycling (up to 15 C) due to the structure’s large surface area. The TiO2 woodpile proved to be a strong candidate for the anode of a high-performance LIB. More importantly, this work demonstrates the great potential of NIL as a platform to create high density architectures for energy storage devices. The strategy described here can be potentially expanded to other electrochemical systems.