Investigation of β/γ-MnO2 in composite electrodes with carbon nanotubes in a redox reaction with lithium in a model accumulator

• Published in: Surface engineering and applied electrochemistry 2014-03, Vol.50 (2), p.125-134
• Main Authors: Apostolova, R. D., Peskov, R. P., Shembel, E. M.
• Format: Article
• Language: English
• Subjects: Engineering; Machines; Manufacturing; Processes
• ISSN: 1068-3755; 1934-8002
• DOI: 10.3103/S1068375514020021

Balastless thin-layer MnO 2 /Al electrodes without an electroconducting carbon additive in combination with multiwalled carbon nanotubes (MWCNT) MnO 2 /Al-MWCNT, as well as bulk-modified paste electrodes MnO 2 (MWCNT) F4/18H12X9T stainless steel electrodes, have been studied in the redox reaction with lithium in a model accumulator on the basis of propylene carbonate (PC), dimetoxiethane (DME), and 1MLiClO 4 and ethyl carbonate (EC), dimethylcarbonate (DMC), and 1M LiClO 4 electrolytes. The window of the electrochemical stability of the anode oxidation on MnO 2 -Al/electrodes in the work range of the potentials for the electrolytes under study is 2.0–4.1 and 2.0–4.2 V, respectively. Because of the high contact resistance between the particles of the thin-layer β/γ-MnO 2 /Al electrode, its discharge capacity cannot exceed 110–120 mA h/g; however, it is stable through 180 cycles. The discharge capacity volume paste MnO 2 , F4/18H12X9T electrodes during the first cycle reaches 265–280 mA h/g and that of the reversible capacity ranges up to 185–250 mA h/g during the first 50 cycles. The role of the aluminum collector in the electrochemical transformation of MnO 2 has been discussed in thin-layer MnO 2 /Al electrodes obtained by the mechanical rubbing of the active component into the aluminum matrix. The lithium chemical diffusion coefficient D Li established in the redox reaction of MnO 2 with lithium has been estimated in thin-layer composite MnO 2 MWCNT/Al electrodes at the current peak values (around 10 −12 cm 2 /s) by slow cyclic voltammetry.