Nanocellulose has been used as a sustainable nanomaterial for constructing advanced electrochemical energy-storage systems with renewability, lightweight, flexibility, high performance, and satisfying safety. Here, we demonstrate a high-performance all-nanofiber asymmetric supercapacitor (ASC) assembled using a forest-based, nanocellulose-derived hierarchical porous carbon (nanocellulose carbon, HPC) anode, a mesoporous nanocellulose membrane separator (nanocellulose separator), and a NiCo2O4 cathode with nanocellulose carbon as the support matrix (nanocellulose cathode, HPC/NiCo2O4). HPC has a three-dimensional porous structure comprising interconnected nanofibers with an ultrahigh surface area of 2046 m2 g–1. When integrated with the mesoporous feature of the nanocellulose membrane separator, these properties facilitate the quick delivery of both ions and electrons even with a thick (up to several hundreds of micrometers) and highly loaded (5.8 mg cm–2) ASC design. Consequently, the all-nanofiber ASC demonstrates a high electrochemical performance (64.83 F g–1 (10.84 F cm–3) at 0.25 A g–1 and 32.78 F g–1 or 5.48 F cm–3 at 4 A g–1) that surpasses most cellulose-based ASCs ever reported. Moreover, the nanocellulose components promise renewability, low cost, and biodegradability, thereby presenting a promising direction toward high-power, environmentally friendly, and renewable energy-storage devices.

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In this paper, we report a flexible comb electrode triboelectric–electret coupling nanogenerator using a separated friction microfiber object for self-powered position, motion direction and acceleration tracking sensing and its energy harvesting.

Lithium extraction from salt lake brines is one of the most important pathways for obtaining Li-related products, e.g., Li2CO3 and LiOH, and for further fabricating electric energy-storage products, e.g., lithium ion batteries. The high Mg/Li ratio and high Mg content are remarkable characteristics of the salt lakes in the Qaidam Basin in China, making the Mg/Li separation and Li extraction rather difficult. Herein, we proposed a reaction-coupled separation technology for Mg/Li separation from brine with a high Mg/Li ratio. The core idea of this technology is that the Mg2+ cations were reacted to form a solid via a nucleation–crystallization separation method. The solid product was MgAl-layered double hydroxide (MgAl-LDH), a widely used and high-valued product in the family of LDHs. The Li+ cations were left in the solution after Mg2+ cations were reacted with alkali solution, accompanied by foreign Al3+ cations. That is to say that the Mg2+ cations can be incorporated into the layers of MgAl-LDH while Li+ cations cannot. The findings indicated that Mg2+ cations were almost completely extracted into the solid phase to form the LDH. The Li+ cations remained in the solution having a weight loss less than 8%, which is an excellent level of Li extraction from the brine with a high Mg/Li ratio. The effects of reaction parameters, e.g., ionic strength, nucleation rotating speed, Mg/Al ratio, and crystallization temperature and time, on the separation performance and lithium loss were investigated. The optimal conditions were derived for lower lithium loss and more outstanding Mg/Li separation performance, which can be a useful guide for environmentally friendly and sustainable Li extraction from the brine.