Toward Solid-State 3D-Microbatteries Using Functionalized Polycarbonate-Based Polymer Electrolytes

Abstract

3D microbatteries (3D-MBs) impose new demands for the selection, fabrication, and compatibility of the different battery components. Herein, solid polymer electrolytes (SPEs) based on poly(trimethylene carbonate) (PTMC) have been implemented in 3D-MB systems. 3D electrodes of two different architectures, LiFePO-coated carbon foams and CuO-coated Cu nanopillars, have been coated with SPEs and used in Li cells. Functionalized PTMC with hydroxyl end groups was found to enable uniform and well-covering coatings on LiFePO-coated carbon foams, which was difficult to achieve for nonfunctionalized polymers, but the cell cycling performance was limited. By employing a SPE prepared from a copolymer of TMC and caprolactone (CL), with higher ionic conductivity, Li cells composed of CuO-coated Cu nanopillars were constructed and tested both at ambient temperature and 60 °C. The footprint areal capacity of the cells was ca. 0.02 mAh cm for an area gain factor (AF) of 2.5, and 0.2 mAh cm for a relatively dense nanopillar-array (AF = 25) at a current density of 0.008 mA cm under ambient temperature (22 ± 1 °C). These results provide new routes toward the realization of all-solid-state 3D-MBs.

Towards smart free form-factor 3D printable batteries

“…The fabrication process of the anode was similar to that of the cathode. Li 4 Ti 5 O 12 (LTO) powder (Life Power C-T2, Sud-Chemie Clariant) was used as an active anode material.…”

“…Our aim is to improve the percolation of the active material with the conducting additives, to enhance liquid-electrolyte impregnation into the composite-polymer electrodes to develop printable solid electrolyte and, nally, a solid-state free form-factor battery. (Li 4 Ti 5 O 12 , LTO, Sud-Chemie Clariant) was used as an active material for the fabrication of anode laments. The LTO-tocarbon and LTO-to-PLA ratios were the same as in the cathode.…”

“…Aer drying the sample, the liquid electrolyte is injected into the channel to fully soak the electrodes. The 3D-printed LiFePO 4 /Li 4 4 (60 wt% solids) inks were prepared by dispersing the particles in ethylene glycol (EG)-water solution. These suspensions were then ball-milled and this was followed by a two-step centrifugation process.…”

“…Our current research is a feasibility study of the fabrication of electrochemically active Li 4 Ti 5 O 12 (LTO)-based anode and LiFePO 4 (LFP)-based cathode laments. To the best of our knowledge, the FFF method for LTO-and LFP-based Li-ion battery electrodes has not been covered in the literature, to date.…”

“…Fig. 3b and c show the ESEM micrographs of the initial and the succeeding steps of the FFF printing of spiral LiFePO 4 -PLA and Li 4 Ti 5 O 12 -PLA electrodes at different magnications. Fig.…”