Sweet Sci­ence

A Vir­gin­ia Tech research team has developed a bat­tery that runs on sug­ar and has an unmatched energy dens­ity, a devel­op­ment that could replace con­ven­tion­al bat­ter­ies with ones that are cheap­er, refil­lable, and bio­de­grad­able. The find­ings from Y.H. Per­civ­al Zhang, an asso­ci­ate pro­fess­or of bio­lo­gic­al sys­tems engin­eer­ing in the Col­lege of Agri­cul­ture and Life Sci­ences and the Col­lege of Engin­eer­ing, were pub­lished in the journ­al Nature Com­mu­nic­a­tions. While oth­er sug­ar bat­ter­ies have been developed, Zhang said this has an energy dens­ity an order of mag­nitude high­er than oth­ers, allow­ing it to run longer before need­ing to be refueled. In as soon as three years, Zhang’s new bat­tery could be run­ning some of the cell phones, tab­lets, video games, and the myri­ad oth­er elec­tron­ic gad­gets that require power in our energy-hungry world. ​“Sug­ar is a per­fect energy stor­age com­pound in nature,” Zhang said. ​“So it’s only logic­al that we try to har­ness this nat­ur­al power in an envir­on­ment­ally friendly way to pro­duce a bat­tery.” In Amer­ica alone, bil­lions of tox­ic bat­ter­ies are thrown away every year, pos­ing a threat to both the envir­on­ment and human health, accord­ing to the Envir­on­ment­al Pro­tec­tion Agency. Zhang’s devel­op­ment could help keep hun­dreds of thou­sands of tons of bat­ter­ies from end­ing up in land­fills. This is one of Zhang’s many suc­cesses in the last year that util­ize a series of enzymes mixed togeth­er in com­bin­a­tions not found in nature. He has pub­lished art­icles on cre­at­ing edible starch from non-food plants and developed a new way to extract hydro­gen in an eco­nom­ic­al and envir­on­ment­ally friendly way that can be used to power vehicles. In this new­est devel­op­ment, Zhang and his col­leagues con­struc­ted a non-nat­ur­al syn­thet­ic enzymat­ic path­way that strips all charge poten­tials from the sug­ar to gen­er­ate elec­tri­city in an enzymat­ic fuel cell. Then, low-cost biocata­lyst enzymes are used as cata­lysts instead of costly plat­in­um, which is typ­ic­ally used in con­ven­tion­al bat­ter­ies. Like all fuel cells, the sug­ar bat­tery com­bines fuel — in this case, malto­dex­trin, a poly­sac­char­ide made from par­tial hydro­lys­is of starch — with air to gen­er­ate elec­tri­city and water as the main byproducts. ​“We are releas­ing all elec­tron charges stored in the sug­ar solu­tion slowly step-by-step by using an enzyme cas­cade,” Zhang said. Dif­fer­ent from hydro­gen fuel cells and dir­ect meth­an­ol fuel cells, the fuel sug­ar solu­tion is neither explos­ive nor flam­mable and has a high­er energy stor­age dens­ity. The enzymes and fuels used to build the device are bio­de­grad­able. The bat­tery is also refil­lable and sug­ar can be added to it much like filling a print­er cart­ridge with ink. Sup­port for the cur­rent research comes from the Depart­ment of Bio­lo­gic­al Sys­tems Engin­eer­ing at Vir­gin­ia Tech and Cell-Free Bioin­nov­a­tions, a biotech start-up, loc­ated in Blacks­burg, Va. Addi­tion­al fund­ing was con­trib­uted by the Nation­al Sci­ence Found­a­tion Small Busi­ness Innov­a­tion Research grant to Cell-Free Bioin­nov­a­tions Inc. Zhi­guang Zhu, the first author of this paper, and a 2013 bio­lo­gic­al sys­tems engin­eer­ing gradu­ate of Vir­gin­ia Tech, is the prin­cip­al invest­ig­at­or for the Nation­al Sci­ence Found­a­tion grant. Source: Vir­gin­ia Tech