EES Blog

New Energy and Environmental Science mini review

Advances on biomass pretreatment using ionic liquids: An overview

Haregewine Tadesse and Rafael Luque

Energy and Environmental Science, DOI: 10.1039/c0ee00667j

With increasing pressure on non-renewable energy and chemical sources due to the Earth’s swelling population and dwindling supplies, research into renewable and environmentally friendly feedstocks is of critical importance. In this Energy and Environmental Science review, the authors Tadesse and Luque set out the current state of affairs in an area of research which sits at the interface of two important areas of science: ionic liquids and biofuels.

The conversion of biomass into useful fuels and chemicals is a complex process. It is of utmost importance that a strategy for this conversion is developed which is low cost, efficient, and minimises the use of volatile organic solvents. A critical step in this process is the pre-treatment of the biomass. In this review the discussion revolves around lignocellulosic biomass, which includes materials like corn stalk and wheat straw. The pre-treatment step removes or weakens the strong linkages between cell wall components in the plant structure, making the biomass easier to break down and improving the eventual yield of useful products. The key point, as set out by the authors, is as follows:

The depolymerization or hydrolysis of lignocellulosics into intermediates that are more susceptible to chemical or biological transformations is a prerequisite step for the production of biofuels and chemicals.

The solvent systems that are currently used for pre-treatment present various difficulties and drawbacks, for example their volatility and the generation of poisonous gases. An exciting alternative to these systems has emerged in the form of ionic liquids, molten ion solutions which melt at temperatures less that 100 °C. These are considered as promising solvents in many areas of chemistry due to their high solvation capacity, negligible vapour pressure and highly tuneable properties.

To read more on this topic, including thorough explanation and detailed analysis of this exciting field of research, click here.

Scientists in China have developed an electrode for lithium-sulfur batteries using pig bones as a cheap and renewable carbon source.

Lithium-sulfur batteries are promising rechargeable batteries because of their high energy storage capacity and low cost, but their use has been hindered by their short life cycle and loss of active sulfur through electrochemical reactions in the battery. Porous carbon materials can help as the sulfur is trapped in the pores, preventing it reacting further, but their preparation involves many synthetic steps.

Now, Yaqin Huang and his team from the Beijing University of Chemical Technology have discovered a porous carbon source in pig bone.

“The development of rechargeable batteries that can be coupled to renewable sources is becoming more important for clean and efficient energy storage,” explains Huang.

Leela Mohana Reddy, an expert in lithium ion batteries and supercapacitors at Rice University, Texas, US, comments that, “pig bone based porous carbon has great potential in the development of novel cathode materials for building the next generation of energy storage devices.”

Read more of the Chemistry World article…

Read the Energy & Environmental Science article today:

Pig bone derived hierarchical porous carbon and its enhanced cycling performance of lithium–sulfur batteries
Shaochen Wei, Hao Zhang, Yaqin Huang, Weikun Wang, Yuzhen Xia and Zhongbao Yu
Energy Environ. Sci., 2011, DOI: 10.1039/c0ee00505c

‘HOT’ Communication article – photovoltaics with >17% efficiency potential

Cu-catalyzed vapor–liquid–solid growth and surface passivation techniques produce crystalline Si microwires of sufficient material quality for high-performance photovoltaics with high efficiency potential.

High-performance Si microwire photovoltaics
Michael D. Kelzenberg, Daniel B. Turner-Evans, Morgan C. Putnam, Shannon W. Boettcher, Ryan M. Briggs, Jae Yeon Baek, Nathan S. Lewis and Harry A. Atwater
Energy Environ. Sci., 2011, DOI: 10.1039/C0EE00549E

Throughout the growth of the photovoltaics (PV) industry, crystalline silicon wafer-based solar cells have remained the predominant worldwide technology due in part to high module efficiencies and the tremendous scale at which they are manufactured. However, producing silicon wafers is costly and energy-intensive, which has enabled lower-cost, less-efficient thin-film PV technologies such as CdTe to gain significant market share in recent years.

Technologies that combine the high efficiency, abundance, and non-toxicity of crystalline Si with the low cost and light weight of thin-film PV have the potential to significantly accelerate the adoption of PV energy.
Now, scientists from the US have investigated crystalline silicon microwires as an alternative to wafers. They made the wires by the vapor-liquid-solid (VLS) process, a thin-film vapour deposition technique and found that they possess remarkably high material quality, potentially enabling silicon microwire-array solar cells to reach efficiencies that rival those of many wafer-based crystalline technologies.