Co‐insertion of Water with Protons into Organic Electrodes Enables High‐Rate and High‐Capacity Proton Batteries

Abstract

Global warming and unprecedented consumption of fossil fuels are driving the increasing interest toward renewable energy sources, such as solar and wind. However, integrating these renewables with electric grids is challenging due to the rapid variability and fluctuations caused by the weather and time of day. This requires energy storage systems to respond within a few seconds, and also provides high energy efficiency to avoid energy dissipation in the meantime. [1] Lithium-ion batteries (LIBs) have been recognized as a suitable candidate for storing grid energy, but are limited by cost and safety. To overcome these limitations, earth-abundant metal ions, such as Na þ , K þ , Zn 2þ , Mg 2þ , and Al 3þ , are being explored as alternative charge carriers. [2][3][4][5][6][7] Unfortunately, because of the higher ionic radius and/or charge number, it becomes increasingly challenging for metal ions to insert into electrode materials to achieve high-rate capability and power density.Protons are ideal charge carriers for use in large-scale energy storage due to its smallest ionic radius with a radius of 0.833 fm, [8,9] ultrafast diffusion kinetics, and negligible costs compared with metal ions. Since the first evidence for hydronium intercalation into a 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) electrode in 2017, [10] more and more proton-storage materials have emerged, including metal oxides (MoO 3 , WO 3 , TiO 2 ), [8,[11][12][13][14] Prussian blue analogs (PBAs), [15][16][17] organic solids (pyrene-4,5,9,10-tetraone [PTO], 2,6-dihydroxyanthraquinone [DHAQ], 2,5-dichloro-1,4-phenylene bis((ethylsulfonyl)amide) [HDC], etc.), [10,[18][19][20] and MXenes. [21] So far, great progress has been achieved toward figuring out proton transport mechanisms within electrode lattices, for example, the bridge oxygen transport in WO 3 •0.6H 2 O, [14] the Grotthuss conduction in Cu[Fe(CN) 6 ] 0.63 •□ 0.37 •3.4H 2 O (□ represents a ferricyanide vacancy), [15] and the quinone/hydroquinone redox reaction in PTO. [20] However, the understanding on the proton intercalation behavior at the electrode-electrolyte interface has remained limited to date, although such behavior was proven to be central to the electrochemical performance of proton topochemistry. [8] The interface exercises a critical control on the charge/ discharge rate performance. In some battery systems, the ratelimiting step is the interfacial reaction rather than the transport of charge-carrier ions within electrode bulk. [22][23][24] In aqueous batteries, the water-solvated charge carriers usually undergo a typical desolvation process prior to the insertion into the electrode material. [22] However, because of the high (de)solvation

WITHDRAWN: Facile synthesis of monoclinic ammonium vanadate nanoflower and their applications for Aqueous ammonium-ion battery

“…Since the pioneering work of Dahn in 1994, who designed the rst water-based lithium-ion battery, extensive research has been conducted on various metal ions, including K + [1] , Na + [2] , Zn 2+ [3] , Mg 2+ [4] , Ca 2+ [5] , and Al 3+ [6] , as charge carriers. In recent years, aqueous non-metal ion batteries, including NH 4+ [7] , H + [8] , H 3 O + [9] , have gained increasing attention. Among the numerous non-metal cations, the ammonium ion (NH 4+ ) as a charge carrier exhibits more prominent attractiveness in terms of ultra-fast ion diffusion kinetics in low corrosive and low hydrogen evolution water electrolytes, as well as safety, resource abundance, and low-cost sustainable development advantages.…”

Aqueous Organic Batteries Using the Proton as a Charge Carrier

“…Despite PTO proving its worth as an excellent anode for proton storage, it is still not very clear how proton intercalation occurs at the electrode‐electrolyte interface. Zhao's group [ 100 ] used ex situ thermogravimetric analysis (TGA) and electrochemical quartz crystal microbalance measurements to record the mass changes of the PTO electrode during the charging/discharging process. The large‐scale mass changes for the PTO electrode indicate that H 2 O molecules and protons get into the lattice of the PTO together, where the charges of protons can be effectively shielded for the existence of H 2 O molecules.…”

“…Despite PTO proving its worth as an excellent anode for proton storage, it is still not very clear how proton intercalation occurs at the electrode-electrolyte interface. Zhao's group [100] The successful application of PTO has stimulated researchers to develop more quinone-based compounds as the anode for APBs. Meanwhile, it is very important to unveil the chargestorage mechanisms of quinone-based compounds during the redox processes.…”

Rational Design of Electrode–Electrolyte Interphase and Electrolytes for Rechargeable Proton Batteries

“…Our group has reported the co-insertion of water molecules and proton into the PTO anode and revealed the incomplete desolvation process and effectively reduces interfacial resistance (Fig. 2 b) [ 44 ]. An outstanding rate performance up to 250 C and as short as 7 s per charge/discharge is achieved.…”