Dendritic Nanostructured Waste Copper Wires for High-Energy Alkaline Battery

Rechargeable alkaline batteries(RABs)have received remarkable attention in the past decade for their high energy,low cost,safe operation,facile manufacture,and ecofriendly nature.To date,expensive electrode materials and current collectors were predominantly applied for RABs,which have limited their real-world efficacy.In the present work,we propose a scalable process to utilize electronic waste(e-waste)Cu wires as a cost-effective current collector for high-energy wire-type RABs.Initially,the vertically aligned CuO nanowires were prepared over the waste Cu wires via in situ alkaline corrosion.Then,both atomiclayer-deposited NiO and NiCo-hydroxide were applied to the CuO nanowires to form a uniform dendritic-structured NiCo-hydroxide/NiO/CuO/Cu electrode.When the prepared dendritic-structured electrode was applied to the RAB,it showed excellent electrochemical features,namely high-energy-density(82.42 Wh kg−1),excellent specific capacity(219 mAh g−1),and long-term cycling stability(94%capacity retention over 5000 cycles).The presented approach and material meet the requirements of a cost-effective,abundant,and highly efficient electrode for advanced eco-friendly RABs.More importantly,the present method provides an efficient path to recycle e-waste for value-added energy storage applications.

Thermal cracking of waste printed wiring boards for mechanical recycling by using residual steam preprocessing

Mechanical waste-processing methods,whichcombine crushing and separation processes for therecovery of valuable materials,have been widely appliedin waste printed wiring board(PWB)treatment.However,both the high impact toughness and the tensile and flexuralstrengths of whole PWB with a laminated structure resultin great energy consumption and severe abrasion of thecutters during multi-level crushing.In addition,the hightemperatures occurring in continual crushing probablycause the decomposition of the polymer matrix.A thermalcrackmethod using residual steam as the heating mediumhas been developed to pre-treat waste PWBs.Thistreatment reduces the mechanical strength in order toimprove the recovery rate of valuable materials insubsequent mechanical recycling.The changes of thePWBs’macro-mechanical properties were studied toevaluate thermal expansion impacts associated withchanges in temperature,and the dynamic dislocationmicro-structures were observed to identify the fracturemechanism.The results showed that thermal cracking withsteam at the temperature of 500 K can effectively attenuatethe mechanical properties of waste PWBs,by reducing theimpact,tensile and flexural strengths respectively,by59.2%,49.3%and 51.4%,compared to untreated PWB.Thermal expansion can also facilitate the separation ofcopper from glass fiber by reducing peel resistance by95.4%at 500 K.It was revealed that the flexural fracturewas a transverse cracking caused by concentrated stresswhen the heating temperature was less than 500 K,andshifted to a vertical cracking after exceeding 500 K.