Direct Borohydride Fuel Cell or DBFCs are a subcategory of Proton-exchange fuel cells where the fuel is a solution of Sodium borohydride. Proton exchange membrane fuel cells, also known as polymer electrolyte membrane fuel cells (PEMFC), are a type of fuel cell being developed for transport applications as well as for stationary and portable applications. ... Sodium borohydride, also known as sodium tetrahydridoborate, has the chemical formula NaBH4 (CAS 16940-66-2). ...

Sodium borohydride is also used in experimental fuel cell systems as a means of storing hydrogen. As a fuel it is less flammable and less volatile than gasoline but much more corrosive. It is relatively environmentally friendly because it will quickly degrade into inert salts when released into the environment. The hydrogen can be regenerated for a fuel cell by catalytic decomposition of the aqueous borohydride solution: A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Gasoline, as it is known in North America, or petrol, in many Commonwealth countries (sometimes also called motor spirit) is a petroleum-derived liquid mixture consisting primarily of hydrocarbons, used as fuel in internal combustion engines. ... A catalyst (Greek: καταλύτης, catalytēs) is a substance that accelerates the rate (speed) of a chemical reaction (see also catalysis). ...

NaBH₄ + 2H₂O → NaBO₂ + 4H₂

Direct Borohydride Fuel Cells (DBFC) decompose and oxidize this fuel directly, side-stepping hydrogen production and even producing slightly higher energy yields:

Fuel Cell's Cathode: 2O₂ + 4H₂O + 8e^- => 8OH^- E⁰=.4v

Fuel Cell's Anode: NaBH₄ + 8OH^- => NaBO₂ + 6H₂O + 8e^- E⁰=1.24v Total E⁰=1.64v

DBFCs could be produced more cheaply (because they do not need expensive platinum catalysts) and provide higher power output per mass than a traditional fuel cell. Unfortunately, DBFCs do produce some hydrogen from a side step reaction of NaBH₄ with water heated by the fuel cell. This hydrogen can either be piped out to the exhaust or piped to a conventional hydrogen fuel cell. Either fuel cell will produce water, and the water can be recycled to allow for higher concentrations of NaBH₄. The volt is the SI derived unit for electric potential and voltage (derived from the ampere and watt). ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... A catalyst (Greek: καταλύτης) is a substance that accelerates the rate of a chemical reaction, at some temperature, but without itself being transformed or consumed by the reaction (see also catalysis). ...

After releasing its hydrogen and being oxidized, NaBO₂ or Borax is produced. Borax is relatively inert and non-toxic; it is a common detergent and soap additive, though it is toxic to ants and is an ingredient of ant poisons. The borax waste can be pumped into a waste tank or bladder inside the fuel tank. Borax is a somewhat generic name used to describe a number of closely related minerals or chemical compounds: anhydrous borax (Na2B4O7) borax pentahydrate (Na2B4O7 Â· 5H2O) borax decahydrate (Na2B4O7 Â· 10H2O) The borax term is most usually used to describe borax decahydrate. ...

Borax can be hydrogenated back into borohydride fuel by several different techniques, some of which require nothing more than water and electricity or heat. These techniques are still in active development.

Sodium borohydride costs US$50 per kg, but with borax recycling and mass production projected prices for the fuel are as low as US$1/kg. The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ...