Influenced by the substantial growth of portable consumer electronic devices, the research on flexible solid-state energy storage devices has become a focus. Polymer electrolyte membranes play a critical role in the development of energy storage system and flexible solid-state supercapacitor. The fact that traditional polymer electrolyte membranes can neither be obtained from renewable materials nor be degraded biologically coupled with its complicated synthesis process have considerable influence on its extensive application. Recently, a research team led by Prof. Yu Haipeng of the Key Laboratory of Biomass Materials Science and Technology of College of Materials Science and Engineering sponsored by the Ministry of Education has put forward a new method of the synthesis of electrolyte membranes of cellulose mesopores and developed flexible solid-state supercapacitors and mircrocapacitors on this basis, which display excellent properties.The relevant achievements have been published in the online version ofAdvanced Energy Materials（http://dx.doi.org/10.1002/aenm.201700739).

Zhao Dawei, the first author of this academic paper, introduces that this research has synthesized renewable and biologically degradable membranes of cellulose mesopores (mCel membranes) by applying the phase inversion method with ionic liquid as agent, which serves as an accessible and extensible method of the synthesis of electrolyte membranes of cellulose mesopores (mCel membranes). The synthesized mCel membranes possess the merits such as micropores and mesopores with even distribution and adjustable sizes, high porosity and transparency, superb flexibility and mechanical strength, high retention rate of electrolytic solution after saturation in KOH solution and ionic conductivity, which are achieved in a single renewable and degradable material for the first time. On the basis of these properties, flexible solid-state supercapacitors synthesized by mCel electrolyte membranes and activated carbon electrodes can display relatively high specific capacitance and optimal cyclicity. Another remarkable value of the application of this type of electrolyte membranes is that it can facilitate the direct deposition of electrode materials on mCel polymer electrolyte membranes without the use of adhesion agent or intricate devices, which can manufacture microcapacitors with a variety of model types in a straightforward but smart manner. The above findings show that this research offers a simple, effective and extensible method, which indicates the potential direction of the synthesis of flexible and biologically degradable cellulose mesoporous membranes and the manufacturing of portable energy storage devices.

The research has been supported by both the National Natural Science Foundation of China and the Science Foundation of Heilongjiang Province for Outstanding Young Scientists.