Electrochemically Controlled Deposition of Ultrathin Polymer Electrolyte on Complex Microbattery Electrode Architectures

Abstract

Solid state microbatteries are highly sought after for emerging microsensor technologies. To overcome the problem of the dwarfing capacity resulting from the miniaturization of the battery, 3D-structured platform consisting of high surface area micropillar-shaped electrodes are used. However, applying a conformal and continuous solid polymer electrolyte films onto the intricate 3D electrodes is a crucial step toward achieving functional microbatteries. In this work, we present our approach for the development of polyethylene oxide (PEO)-acrylate based ion conducting polymer thin films which function as solid polymer electrolyte (SPE) and a separator. The SPEs were electrochemically deposited on the 3D electrodes resulting in ultrathin, continuous, conformal, and pinhole-free polymer films. The electrochemical and Li + ions transport properties of the SPEs were characterized by EIS measurements and cyclic voltammetry. Furthermore, the homogenous composition of the SPEs at various depths were confirmed by XPS depth profiling techniques.

Recent advancements in solid electrolytes integrated into all-solid-state 2D and 3D lithium-ion microbatteries

“…75 Recently Abdelhamid et al electrochemically graed and polymerized (PEO)-acrylate-based electrolyte and obtained pinhole-free and homogeneous lm on 3D metal cylindrical micropillars. 109 The resulting electrolyte had relatively high ionic conductivity (10 À4 S cm À1 ). 109 Although the testing of microbattery has not been conducted, it is expected that homogeneous SPE lm will positively impact the microbattery performance.…”

“…109 The resulting electrolyte had relatively high ionic conductivity (10 À4 S cm À1 ). 109 Although the testing of microbattery has not been conducted, it is expected that homogeneous SPE lm will positively impact the microbattery performance. Moreover, this approach was shown as a promising way to control electrolyte formation by varying the potential and duration of the polymerization process.…”

“…74,75,96,108,110 This method also introduced easier control of lm's thickness by potential and time variation and lower electrolyte-electrode interface resistances. 109,301 However, this method is cumbersome and requires relatively complex material preparations. Thus, other techniques are also under development.…”

Trade‐offs between ion‐conducting and mechanical properties: The case of polyacrylate electrolytes

“…PEGMA undertakes dual functions—forming SEI layers via lithium metal‐induced anionic polymerization and transforming into a high‐modulus solid at high‐temperatures (over 130°C) to intelligently respond to environmental degradation. Moreover, Abdelhamid et al proposed a self‐limiting electrochemically controlled deposition of PEGMA, which induces a uniform and ultrathin conformal SPE layer covering complicated microelectrodes 135 …”

“…Moreover, Abdelhamid et al proposed a self-limiting electrochemically controlled deposition of PEGMA, which induces a uniform and ultrathin conformal SPE layer covering complicated microelectrodes. 135 The Li + -ion transport behavior in EO-PA SPEs is directly correlated to the dynamics of EO side chains. The majority of efforts should concentrate on how to expand amorphous domains simultaneously balancing the Li + -ion solvation state and the connectivity of solvation sites.…”