An All-Organic Proton Battery

Abstract

Rechargeable batteries that use organic matter as the capacity-carrying material have previously been considered a technology for the future. Earlier batteries in which both the anode and cathode consisted of organic material required significant amounts of conductive additives and were often based on metal-ion electrolytes containing Li or Na. However, we have used conducting poly(3,4-ethylenedioxythiophene) (PEDOT), functionalized with anthraquinone (PEDOT-AQ) or benzonquinone (PEDOT-BQ) pendant groups as the negative and positive electrode materials, respectively, to make an all-organic proton battery devoid of metals. The electrolyte consists of a proton donor and acceptor slurry containing substituted pyridinium triflates and the corresponding pyridine base. This slurry allows the 2e/2H quinone/hydroquinone redox reactions while suppressing proton reduction in the battery cell. By using strong (acidic) proton donors, the formal potential of the quinone redox reactions is tuned into the potential region in which the PEDOT backbone is conductive, thus eliminating the need for conducting additives. In this all-organic proton battery cell, PEDOT-AQ and PEDOT-BQ deliver 103 and 120 mAh g, which correspond to 78% and 75%, respectively, of the theoretical specific capacity of the materials at an average cell potential of 0.5 V. We show that PEDOT-BQ determines the cycling stability of the device while PEDOT-AQ provides excellent reversibility for at least 1000 cycles. This proof-of-concept shows the feasibility of assembling all-organic proton batteries which require no conductive additives and also reveals where the challenges and opportunities lie on the path to producing plastic batteries.

Sustainable Energy Storage: Recent Trends and Developments toward Fully Organic Batteries

“…showed an all‐organic cell, which used poly(EDOT–benzoquinone) and poly(EDOT–anthraquinone) as active electrode materials as well as a metal‐free, pyridine‐based electrolyte (Figure ). However, the cell featured an unstable voltage and capacity …”

“…Bottom: Related electrochemical characteristics, in particular the cyclovoltammograms of the active materials poly(EDOT‐anthraquinone) and poly(EDOT‐benzoquinone) (left), the charge/discharge voltage curve of a respective cell (middle), and a differential capacity plot derived from the latter data resembling the voltammetry experiment (right). (Reprinted with permission from the American Chemical Society, Copyright 2017) …”

“…However, the cell featured an unstable voltagea nd capacity. [62] In summary,q uinones still represent the mostp opulara nd promisingc lass of organica ctive electrode materials in terms of specific capacity and stability,i np articular when they are integrated in polymeric compounds. Thus, several all-organic systems have been presented that are based partly or solely on quinone derivatives.…”

“…[74] The resulting workingv oltage strongly decreased during the discharge, but the capacity loss was only 15 %o ver 700 cycles (Figure8,r ight).L ikewise, Lu et al built af ully or-ganic cell from an ethylene-linked perylened iimide polymer and polytriphenylamineu sing Mg(ClO 4 ) 2 in the electrolyte. [75] Again, the discharge voltage was slightly sloping with an aver- [62] Scheme4.To p: Molecular structures of commonaromatic diimides with theoretical specific capacities. Bottom:General redox mechanism of aromatic diimides.…”

An Environmentally Friendly and Flexible Aqueous Zinc Battery Using an Organic Cathode

“…[18][19][20][21][22][23][24] Several cathodes materials,s uch as copper hexacyanoferrate, [20] V 2 O 5 , [21,22] and MnO 2 , [23,24] have been coupled with the zinc anode to form the rechargeable aqueous zinc batteries.I nt hese reports,c athodes still involve toxic and/or environmentally unfriendly elements in their components.V ery recently,o rganic electrode materials have been considered as the low-toxicity and sustainable alternative to conventional inorganic electrode materials. [25][26][27][28][29][30][31][32][33][34][35][36] In theory,the combination of organic cathode and zinc anode in mild electrolyte should be ap romising approach for developing low toxic battery,b ecause some organics show very limited toxicity.However,the academic results on this topic are rarely reported. Only very recently,C hen et al first reported an aqueous zinc battery using aq uinone (C4Q)-cathode,w hich shows ah igh energy density.…”