The anode/electrolyte interface behavior, and by extension, the overall cell
performance of sodium-ion batteries is determined by a complex interaction
of processes that occur at all components of the electrochemical cell across a
wide range of size- and timescales. Single-scale studies may provide
incomplete insights, as they cannot capture the full picture of this complex
and intertwined behavior. Broad, multiscale studies are essential to elucidate
these processes. Within this perspectives article, several analytical and
theoretical techniques are introduced, and described how they can be
combined to provide a more complete and comprehensive understanding of
sodium-ion battery (SIB) performance throughout its lifetime, with a special
focus on the interfaces of hard carbon anodes. These methods target various
length- and time scales, ranging from micro to nano, from cell level to
atomistic structures, and account for a broad spectrum of physical and
(electro)chemical characteristics. Specifically, how mass spectrometric,
microscopic, spectroscopic, electrochemical, thermodynamic, and physical
methods can be employed to obtain the various types of information required
to understand battery behavior will be explored. Ways are then discussed how
these methods can be coupled together in order to elucidate the multiscale
phenomena at the anode interface and develop a holistic understanding of
their relationship to overall sodium-ion battery function.
