Boosting syngas production through catalytic thermochemistry of biomass waste and spent lithium-ion batteries

In response to current energy scarcity and the need to reduce greenhouse gas emissions, efficient and sustainable conversion of the renewable biomass wastes into gaseous fuels has garnered an increasing attention. While the identification and deactivation of suitable catalyst are still challenging during the gasification pyrolysis process through the conversion of biomass waste into targeted gases. Herein, waste cathode materials derived from spent lithium-ion batteries (LIBs) were innovatively used as catalysts for the catalytic cracking of waste corn straw (CS) into energy gases towards their simultaneous recycling into valuable metals. Catalytic pyrolysis experimental results suggested that directional conversion into energy gases of H2 and CO can be achieved under optimized operational conditions. In the moderated pyrolysis temperature range of 450–550 °C, the content of H2 in pyrolytic gases can reach as high as 45.82 %, while CO will account for 10.98 % of the total gas composition and become one of another main energy gases at the pyrolysis temperature over 650 °C. Simultaneously, waste cathode materials, i.e. LiNixCoyMn1-x-yO2 (NCM), LiCoO2 (LCO) and LiMn2O4 (LMO), were controllably converted into their recyclable states (Li2CO3, TMO or TM, TM = Ni, Co, Mn). It can be also revealed from the pyrolysis mechanism of CS that the Ni/Co based catalysts of NCM and LCO will facilitate the production of H2 due to their reforming of oxygenated compounds and hydrocarbons, while increased amount of CO was generated from the catalysis of LMO via promoted reverse water-gas shift reaction (RWGS). This study can offer a bidirectional route towards the synergetic conversion of different wastes into valuable resources with sustainable catalytic engineering.