Dendrite-Suppressing\nThree-Dimensional Frameworks\nEnabled by Electrowriting for Anode-Free Batteries

A solution electrowriting method was developed to enable\nreversible\nlithium (Li) plating and stripping processes for anode-free Li batteries.\nThis method merges the broad applicability of electrospinning with\nthe precision inherent in three-dimensional (3D) printing to create\nmicroporous, intricate structures (e.g., a square-grid) from poly(vinylidene\nfluoride) (PVDF) fibers on copper substrates. The breakthrough hinges\non precise control of the rheological, chemical, and mechanical properties\nof PVDF solutions. Square-grid construction of PVDF fibers on copper\nthat serve as a working current collector can make Li plating and\nstripping reversible over an extended number of cycles. Furthermore,\ntailoring the electrical conductivity and lithiophilicity of PVDF\nfibers leads to marked improvements in Li cycling efficiency. The\norigin of excellent Li cycling stability can be closely linked to\nthe formation of peculiar solid-electrolyte interphases (SEIs), which\ngrow denser at the Li plating surface, diminishing the likelihood\nof dendrite penetration in subsequent cycles. The elasticity of the\npolymer framework is essential in preserving the integrity of densifying\nSEIs, averting the development of cracks upon Li plating. This manufacturing\ninnovation lays down a fundamental design principle to surmount the\ncurrent limitations of anode-free batteries and can be extended to\nother energy storage systems encountering electrochemomechanical challenges\nin redox operation.