New lithium ion bat­tery made of mush­rooms

The Witness - Wheels - - MOTORING - NICK LAVARS

CAN porta­bella mush­rooms stop lithium ion bat­ter­ies from de­grad­ing over time?

Re­searchers at the Univer­sity of Cal­i­for­nia, River­side Bourns Col­lege of En­gi­neer­ing, think so.

They have cre­ated a new type of lithium ion bat­tery anode us­ing porta­bella mush­rooms, which are in­ex­pen­sive, en­vi­ron­men­tally friendly and easy to pro­duce.

The cur­rent industry stan­dard for recharge­able lithium ion bat­tery an­odes is syn­thetic graphite, which comes with a high cost of manufacturing be­cause it re­quires te­dious pu­rifi­ca­tion and prepa­ra­tion pro­cesses that are also harm­ful to the en­vi­ron­ment.

With the an­tic­i­pated in­crease in bat­ter­ies needed for elec­tric ve­hi­cles and elec­tron­ics, a cheaper and sus­tain­able source to re­place graphite is needed. Us­ing biomass, a bi­o­log­i­cal ma­te­rial from liv­ing or re­cently liv­ing or­gan­isms, as a re­place­ment for graphite, has drawn re­cent at­ten­tion be­cause of its high car­bon con­tent, low cost and en­vi­ron­men­tal friend­li­ness.

UC River­side en­gi­neers were drawn to us­ing mush­rooms as a form of biomass be­cause past re­search has es­tab­lished they are highly por­ous, mean­ing they have a lot of small spa­ces for liq­uid or air to pass through. That poros­ity is im­por­tant for bat­ter­ies be­cause it cre­ates more space for the stor­age and trans­fer of en­ergy, a crit­i­cal com­po­nent to im­prov­ing bat­tery per­for­mance.

In ad­di­tion, the high potas­sium salt con­cen­tra­tion in mush­rooms al­lows for in­creased elec­trolyte-ac­tive ma­te­rial over time by ac­ti­vat­ing more pores, grad­u­ally in­creas­ing its ca­pac­ity.

A con­ven­tional anode al­lows lithium to ac­cess fully most of the ma­te­rial dur­ing the first few cy­cles and ca­pac­ity fades from elec­trode dam­age oc­curs from that point on. The mush­room car­bon anode tech­nol­ogy could, with op­ti­mi­sa­tion, re­place graphite an­odes. It also pro­vides a binder­less and cur­rent-col­lec­tor free ap­proach to anode fabri­ca­tion.

“With bat­tery ma­te­ri­als like this, fu­ture cell­phones may see an in­crease in run time af­ter many uses, rather than a de­crease, due to ap­par­ent ac­ti­va­tion of blind pores within the car­bon ar­chi­tec­tures as the cell charges and dis­charges over time,” said Bren­nan Camp­bell, a grad­u­ate stu­dent in the ma­te­ri­als sci­ence and en­gi­neer­ing pro­gramme at UC River­side. The re­search find­ings were out­lined in a pa­per, “Bio-De­rived, Binder­less, Hi­er­ar­chi­cally Por­ous Car­bon An­odes for Li-ion Bat­ter­ies”, pub­lished in the jour­nal Sci­en­tific Re­ports. It was au­thored by Cen­giz Ozkan and Mihri Ozkan, both pro­fes­sors in the Bourns Col­lege of En­gi­neer­ing, and three of their cur­rent or former grad­u­ate stu­dents: Camp­bell, Robert Ionescu and Zachary Fa­vors.

Nanocar­bon ar­chi­tec­tures de­rived from bi­o­log­i­cal ma­te­ri­als such as mush­rooms can be con­sid­ered a green and sus­tain­able al­ter­na­tive to graphite-based an­odes, said Cen­giz Ozkan, a pro­fes­sor of me­chan­i­cal en­gi­neer­ing and ma­te­ri­als sci­ence and en­gi­neer­ing.

The nano-rib­bon-like ar­chi­tec­tures trans­form upon heat treat­ment into an in­ter­con­nected por­ous net­work ar­chi­tec­ture which is im­por­tant for bat­tery elec­trodes be­cause such ar­chi­tec­tures pos­sess a very large sur­face area for the stor­age of en­ergy, a crit­i­cal com­po­nent to im­prov­ing bat­tery per­for­mance.

One of the prob­lems with con­ven­tional car­bons, such as graphite, is that they are typ­i­cally pre­pared with chem­i­cals such as acids and ac­ti­vated by bases that are not en­vi­ron­men­tally friendly, said Mihri Ozkan, a pro­fes­sor of elec­tri­cal and com­puter en­gi­neer­ing. There­fore, the UC River­side team are fo­cused on nat­u­rally de­rived car­bons, such as the skin of the caps of porta­bella mush­rooms, for mak­ing bat­ter­ies.

It is ex­pected that nearly 900 000 tons of nat­u­ral raw graphite would be needed for anode fabri­ca­tion for nearly six mil­lion elec­tric ve­hi­cles fore­cast to be built by 2020.

This re­quires that the graphite be treated with harsh chem­i­cals, in­clud­ing hy­droflu­o­ric and sul­fu­ric acids, a process that cre­ates large quan­ti­ties of haz­ardous waste. The Euro­pean Union projects this process will be un­sus­tain­able in the fu­ture.

The Ozkans’ re­search is sup­ported by the Univer­sity of Cal­i­for­nia, River­side.

This pa­per in­volv­ing mush­rooms is pub­lished just over a year af­ter the Ozkans’ labs de­vel­oped a lithium-ion bat­tery anode based on nanosil­i­con via beach sand as the nat­u­ral raw ma­te­rial. The Ozkans’ team are cur­rently work­ing on the de­vel­op­ment of pouch pro­to­type bat­ter­ies based on nanosil­i­con an­odes.

The UCR Of­fice of Tech­nol­ogy Com­mer­cial­i­sa­tion has filed patents.

— Giz­mag.

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