Dendrite-Suppressing Three-Dimensional Frameworks Enabled by Electrowriting for Anode-Free Batteries

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