Shen J. Dillon, University of Illinois, Urbana, IL, USA, and Jennifer A. Lewis, Harvard University, Cambridge, MA, USA, printed 3D Li-ion microbatteries with extremely high energy and power densities.

The 3D interdigitated microbattery architecture (3D-IMA) is fabricated on a gold current collector by printing viscoelastic Li₄Ti₅O₁₂ (LTO) and LiFePO₄ (LFP) inks through 30 µm nozzles, followed by sintering and packaging. LTO serves as anode, LFP as cathode. The facile 3D printing technique allows the functional inks to be precisely patterned in filamentary form over areas ranging from 100 µm² to 1 m² with minimum feature sizes as small as 1 µm.

Using this LFP-LTO chemistry, 3D-IMA with a high areal energy density of 9.7 J cm⁻² at a power density of 2.7 mW cm⁻² have been demonstrated.

The authors say that these microbatteries may find potential application in autonomously powered microelectronics and biomedical devices.

• 3D Printing of Interdigitated Li-Ion Microbattery Architectures,
  Ke Sun, Teng-Sing Wei, Bok Yeop Ahn, Jung Yoon Seo, Shen J. Dillon, Jennifer A. Lewis,
  Adv. Mat. 2013.
  DOI: 10.1002/adma.201301036