Biomass-derived materials for electrochemical energy storages

During the past decade humans have witnessed dramatic expansion of fundamental research as well as the commercialization in the area of electrochemical energy storage, which is driven by the urgent demand by portable electronic devices, electric vehicles, transportation and storage of renewable energy for the power grid in the clean energy economy. Li-secondary batteries and electrochemical capacitors can efficiently convert stored chemical energy into electrical energy, and are currently the rapid-growing rechargeable devices. However, the characteristic (including energy density, cost, and safety issues, etc.) reported for these current rechargeable devices still cannot meet the requirements for electric vehicles and grid energy storage, which are mainly caused by the limited properties of the key materials (e.g. anode, cathode, electrolyte, separator, and binder) employed by these devices. Moreover, these key materials are normally far from renewable and sustainable. Therefore great challenges and opportunities remain to be realized are to search green and low-cost materials with high performances. A large number of the properties of biomass materials-such as renewable, low-cost, earth-abundant, specific structures, mechanical property and many others-are very attractive. These properties endow that biomass could replace some key materials in electrochemical energy storage systems. In this review, we focus on the fundamentals and applications of biomass-derived materials in electrochemical energy storage techniques. Specifically, we summarize the recent advances of the utilization of various biomasses as separators, binders and electrode materials. Finally, several perspectives related to the biomass-derived materials for electrochemical energy storages are proposed based on the reported progress and our own evaluation, aiming to provide some possible research directions in this field.