Silver-Hydrogen Energy Storage.

Equilibrium‐open‐circuit potentials of normalLi/LiClO4 , PC/NbSex false(x=2,3,4,4.5false) cells were measured as a function of the state of charge of these cells. For NbSe2 the emf decreased monotonically from ∼2.3 to 1.65V at full discharge (1 Li/Nb) and was independent of prior history. With NbSe3 two distinct types of emf curves were found: (i) a constant emf of ∼1.7V from 0–2Li/ Nb followed by a monotonic decrease in emf to ∼1.5V at 3Li/Nb, and (ii) a “stepped” form with breaks at 1 and 2Li/Nb. Neither type of curve was reproduced on cycling. The emf of NbSe4 and NbSe4.5 was nearly constant at 1.83V to ∼4Li/Nb. The NbSe4 exhibits a monotonic decrease in emf to ∼1.6V at 5Li/Nb. The emf curves obtained on the first charge and subsequent cycles were higher in value. The implications of this data on the chemistry of cell discharge is discussed.

mentioning

confidence: 99%

Equilibrium Properties of Lithium/Niobium Selenide, Nonaqueous Secondary Cells

Carides¹,

Murphy²

1977

“…(10) NbSe2 was reported to be a host material for iodine. The electrochemical activities of the analogous compounds NbS~ (11) and TiS2 ( as received. Propylene carbonate (PC) and tetraglyme were vacuum distilled from lithium while lithium perchlorate (Alfa Inorganics) was vacuum dried at 150~ Separator bags were made from 1 rail thick polypropylene (Celgard KKX-2, Celanese Plastics Company).…”

Section: Methodsmentioning

confidence: 99%

A New Niobium Selenide Cathode for Nonaqueous Lithium Batteries

Murphy¹,

Trumbore²,

Carides³

1977

The γ‐“NbSe4” phase, with a single phase composition range NbSe4.0 to NbSe4.5 , is shown to behave as an electrochemically active, reversible cathode material in nonaqueous lithium cells. The cell data, together with the results of n‐butyl lithium reaction studies, indicate a topotactic reaction to give an Li4NbSe4+x false(x=0–0.5false) discharge product. Cycle data are presented for nonaqueous lithium cells with cathodes of either NbSe4 containing small amounts of fibrous NbSe3 or hot‐pressed composites of NbSe4+x with graphite and polyethylene.

“…Casual examination of Eq. [1]- [3] indicates that the H2 electrode is likely to dry out during the charging step. In practice, drying out of the Ag electrode during charge is the real problem (6).…”

Section: Electrolyte Managementmentioning

confidence: 99%

“…Oxidation of the silver electrode during charging nominally takes place in two steps 2Ag + 2 OH--~ 2e--~ H20 ~ Ag20 [1] Ag20 -~ 2 OH---> 2e--~ H20 -~ 2AgO [2] In alkaline media the relevant reaction at the H2 electrode is 2H20 -t-2e--> Hz -~ 2 OH- [3] so that the overall cell reactions are 2Ag + H20 -* H2 + Ag20 ). In practice, during charging the cell voltage increases sharply to the second plateau after roughly 30% of the ultimate net capacity has been reached; during discharge, the cell voltage drops after about 35% of capacity.…”

mentioning

confidence: 99%

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On the Design of Silver‐Hydrogen Electrochemical Cells

Offenhartz

Holleck

1980

With a projected energy density of 70–110 W‐hr/kg and an estimated lifetime in excess of 1000 cycles, silver‐hydrogen cells represent a promising electrochemical energy storage device for specialized applications. A cell design using a rolled stack configuration is especially attractive. A comprehensive computer simulation has been used to optimize the energy density of such a cell. The parameters considered include: cell geometry, electrode and lead dimensions, water generation and consumption, electrolyte movement, heat generation and dissipation, and active material utilization. The results show that balancing of electrolyte transport processes is essential for stable long term operation. Energy density is a strong function of rate, with incomplete silver electrode utilization the main factor. At higher rates no more than three or four layers can be used if the maximum temperature increase on discharge is to be kept below 5°–10°C to avoid electrolyte loss via evaporation/condensation processes. Conversely, use of only one or two layers leads to an unacceptably high penalty in the energy density.