To support this high-throughput research, the experimental instrument must meet requirements such as maximizing productivity through parallel experiments and automation, compatibility with Ar gas glove box operation, high resistance to corrosion, and working with small amount of sample per experiment. MTI Corporation (Richmond CA, USA) strive to provide highly efficient and economical experimental equipment and solutions for high throughput battery development. In this work, MTI’s efforts on developing experimental instrumentations for high throughput research of solid state Lithium-ion battery are discussed.
MTI’s high throughput experimental solution for solid state Lithium-ion battery is outlined in Fig. 1. First step is the solid electrolyte synthesis and preparation. MTI provides complete solution for ceramic powder synthesis, from solid / liquid dispensing, high throughput milling / mixing, to multi-channel heat processing with high throughput tube furnace. After the high throughput solid electrolyte powder synthesis, MTI’s 6-position, 10 ton max electric hydraulic press and 4-channel, 1” OD tube furnace up to 1700 ºC allow for a high throughput process of conventional sintering method.
Novel sintering techniques, such as spark plasma sintering (SPS) [3] and hydrothermal-assisted cold sintering process (CSP) [4], are also supported by MTI’s instruments. These techniques, whether for the fast processing time of spark plasma sintering, or the low temperature processing capability of cold sintering process, open up possibilities of low cost, rapid fabrication of solid electrolytes, cathode pellets, or even the whole solid electrode-electrolyte stack [3].
Fast solid electrolyte material screening is possible with combinatorial deposition methods. Combinatorial sputtering deposition systems, which uses substrate mask and multiple deposition sources with adjustable tilt and power, are utilized to create compositional spreads and deposit ternary more complicated thin film composition libraries for ceramic electrolyte [5]. An example is MTI’s combinatorial magnetron sputtering system with 5 independent sputtering sources and rotatable 16-sample mask. Combinatorial spray pyrolysis allows rapid screening of ceramic-polymer composite electrolytes. With MTI’s 6-channel combinatorial ultrasonic spray pyrolysis system, various polymer hosts, liquid electrolytes, and ceramic solid electrolyte powder suspensions are concurrently pumped and mixed at different ratios, and sprayed onto the heated stage. By varying the ratio between polymer electrolyte and ceramic electrolyte, a balance between composite electrolyte‘s electrical and mechanical properties can be achieved through the high throughput screening [4, 6].
Second step is rapid composition characterization of the as-synthesized solid electrolyte powder using high throughput, automatic X-ray fluorescence (XRF) instrumentation. MTI’s 32-sample high throughput XRF spectrometer station integrates a compact XRF spectrometer and a high precision XYZ stage with an Ar gas glove box for quick and easy composition analysis from element Ne to Pu.
Finally, the as-prepared solid electrolytes are assembled with electrodes in split cells for high throughput electrochemical testing. MTI’s 8-channel coin split cell kit allows for easy parallel comparison of multiple cells. Temperature dependent testing is of great interest as improved ionic conductivity is usually observed at elevated temperatures. Moreover, to ensure good interfacial contact between electrode and solid electrolyte, a sufficient compressive pressure needs to be applied on the split cell to confine the volume expansion during charge-discharge cycles [7]. In this effort, MTI has developed a battery dilatometer with adjustable compressive pressure, and a heatable lab press for electrochemical testing under controlled pressure and temperature.
[1] Li J, Ma C, Chi M, Liang C, Dudney NJ. Adv. Energy Mater. 2015;5:1401408.
[2] Kim JG, Son B, Mukherjee S, Schupper N, Bates A, Kwon O, et al. J. Power Sources 2015;282:299.
[3] Kali R, Mukhopadhyay A. J. Power Sources 2014;247:920.
[4] Guo J, Berbano SS, Guo H, Baker AL, Lanagan MT, Randall CA. Adv. Funct. Mater. 2016;26:7115.
[5] Beal MS, Hayden BE, Le Gall T, Lee CE, Lu X, Mirsaneh M, et al. ACS Comb. Sci. 2011;13:375.
[6] Zhao Y, Huang Z, Chen S, Chen B, Yang J, Zhang Q, et al. Solid State Ionics 2016;295:65.
[7] Piper DM, Yersak TA, Lee SH. J. Electrochem. Soc. 2013;160:A77.
Fig. 1. MTI’s high throughput experimental solution for solid state Lithium-ion battery research.