Of course cathode materials continue to be a great problem because although there are many novel outstanding materials there are also new important systems requiring cathodes with much greater performances.
As per general answer, always every part of the existing device having scope. while for realistic actually, cathode materials is very important part of the energy device so till other materials improvement is going on cathode materials as well. actually cathode materials having two important work one related to keeping voltage difference second number of charge carriers transferring towards the anode.
If I answer Wei's specific question; short cycle life of binder-free cathode; the volume expansion of cathode materials will be responsible for the short cycle life.. Cathode material continuously change its volume due to repeated Li insertion/extraction during cycling. As a result, crack will be readily generated which may (i) delaminate cathodes from current collector and/or (ii) isolate cathode particles from electrical conduction pathways.